- Reference >
- MongoDB Package Components >
mongod
mongod
¶
On this page
Synopsis¶
mongod
is the primary daemon process for the MongoDB
system. It handles data requests, manages data access, and performs
background management operations.
This document provides a complete overview of all command line options
for mongod
. These command line options are primarily useful
for testing: In common operation, use the configuration file
options to control the behavior of
your database.
Note
Starting in version 4.0, MongoDB disables support for TLS 1.0 encryption on systems where TLS 1.1+ is available. For more details, see Disable TLS 1.0.
Options¶
-
mongod
¶
Core Options¶
-
--help
,
-h
¶
Returns information on the options and use of mongod.
-
--version
¶
Returns the mongod release number.
-
--config
<filename>
,
-f
<filename>
¶ Specifies a configuration file for runtime configuration options. The configuration file is the preferred method for runtime configuration of mongod. The options are equivalent to the command-line configuration options. See Configuration File Options for more information.
Ensure the configuration file uses ASCII encoding. The mongod instance does not support configuration files with non-ASCII encoding, including UTF-8.
-
--verbose
,
-v
¶
Increases the amount of internal reporting returned on standard output or in log files. Increase the verbosity with the
-v
form by including the option multiple times, (e.g.-vvvvv
.)
-
--quiet
¶
Runs mongod in a quiet mode that attempts to limit the amount of output.
This option suppresses:
- output from database commands
- replication activity
- connection accepted events
- connection closed events
-
--port
<port>
¶ Default:
- 27017 if
mongod
is not a shard member or a config server member - 27018 if
mongod
is ashard member
- 27019 if
mongod
is aconfig server member
The TCP port on which the MongoDB instance listens for client connections.
- 27017 if
-
--bind_ip
<hostnames|ipaddresses|Unix domain socket paths>
¶ Default: localhost
Note
Starting in MongoDB 3.6, mongod bind to localhost by default. See Default Bind to Localhost.
The hostnames and/or IP addresses and/or full Unix domain socket paths on which mongod should listen for client connections. You may attach mongod to any interface. To bind to multiple addresses, enter a list of comma-separated values.
Example
localhost,/tmp/mongod.sock
You can specify both IPv4 and IPv6 addresses, or hostnames that resolve to an IPv4 or IPv6 address.
Example
localhost, 2001:0DB8:e132:ba26:0d5c:2774:e7f9:d513
Note
If specifying an IPv6 address or a hostname that resolves to an IPv6 address to
--bind_ip
, you must start mongod with--ipv6
to enable IPv6 support. Specifying an IPv6 address to--bind_ip
does not enable IPv6 support.If specifying a link-local IPv6 address (
fe80::/10
), you must append the zone index to that address (i.e.fe80::<address>%<adapter-name>
).Example
localhost,fe80::a00:27ff:fee0:1fcf%enp0s3
Tip
When possible, use a logical DNS hostname instead of an ip address, particularly when configuring replica set members or sharded cluster members. The use of logical DNS hostnames avoids configuration changes due to ip address changes.
Warning
Before binding to a non-localhost (e.g. publicly accessible) IP address, ensure you have secured your cluster from unauthorized access. For a complete list of security recommendations, see Security Checklist. At minimum, consider enabling authentication and hardening network infrastructure.
For more information about IP Binding, refer to the IP Binding documentation.
To bind to all IPv4 addresses, enter
0.0.0.0
.To bind to all IPv4 and IPv6 addresses, enter
::,0.0.0.0
or alternatively, use thenet.bindIpAll
setting.Note
--bind_ip
and--bind_ip_all
are mutually exclusive. Specifying both options causes mongod to throw an error and terminate.
-
--bind_ip_all
¶
New in version 3.6.
If specified, the mongod instance binds to all IPv4 addresses (i.e.
0.0.0.0
). If mongod starts with--ipv6
,--bind_ip_all
also binds to all IPv6 addresses (i.e.::
).mongod only supports IPv6 if started with
--ipv6
. Specifying--bind_ip_all
alone does not enable IPv6 support.Warning
Before binding to a non-localhost (e.g. publicly accessible) IP address, ensure you have secured your cluster from unauthorized access. For a complete list of security recommendations, see Security Checklist. At minimum, consider enabling authentication and hardening network infrastructure.
For more information about IP Binding, refer to the IP Binding documentation.
Alternatively, you can set the
--bind_ip
option to::,0.0.0.0
to bind to all IP addresses.Note
--bind_ip
and--bind_ip_all
are mutually exclusive. That is, you can specify one or the other, but not both.
-
--clusterIpSourceWhitelist
<string>
¶ New in version 3.6.
A list of IP addresses/CIDR (Classless Inter-Domain Routing) ranges against which the
mongod
validates authentication requests from other members of the replica set and, if part of a sharded cluster, themongos
instances. Themongod
verifies that the originating IP is either explicitly in the list or belongs to a CIDR range in the list. If the IP address is not present, the server does not authenticate themongod
ormongos
.--clusterIpSourceWhitelist
has no effect on amongod
started without authentication.--clusterIpSourceWhitelist
accepts multiple comma-separated IPv4/6 addresses or Classless Inter-Domain Routing (CIDR) ranges:Important
Ensure
--clusterIpSourceWhitelist
includes the IP address or CIDR ranges that include the IP address of each replica set member ormongos
in the deployment to ensure healthy communication between cluster components.
-
--ipv6
¶
Enables IPv6 support. mongod disables IPv6 support by default.
Setting
--ipv6
does not direct the mongod to listen on any local IPv6 addresses or interfaces. To configure the mongod to listen on an IPv6 interface, you must either:- Configure
--bind_ip
with one or more IPv6 addresses or hostnames that resolve to IPv6 addresses, or - Set
--bind_ip_all
totrue
.
- Configure
-
--listenBacklog
<number>
¶ Default: Target system
SOMAXCONN
constantNew in version 3.6.
The maximum number of connections that can exist in the listen queue.
Warning
Consult your local system’s documentation to understand the limitations and configuration requirements before using this parameter.
Important
To prevent undefined behavior, specify a value for this parameter between
1
and the local systemSOMAXCONN
constant.The default value for the
listenBacklog
parameter is set at compile time to the target systemSOMAXCONN
constant.SOMAXCONN
is the maximum valid value that is documented for the backlog parameter to the listen system call.Some systems may interpret
SOMAXCONN
symbolically, and others numerically. The actual listen backlog applied in practice may differ from any numeric interpretation of theSOMAXCONN
constant or argument to--listenBacklog
, and may also be constrained by system settings likenet.core.somaxconn
on Linux.Passing a value for the
listenBacklog
parameter that exceeds theSOMAXCONN
constant for the local system is, by the letter of the standards, undefined behavior. Higher values may be silently integer truncated, may be ignored, may cause unexpected resource consumption, or have other adverse consequences.On systems with workloads that exhibit connection spikes, for which it is empirically known that the local system can honor higher values for the backlog parameter than the
SOMAXCONN
constant, setting thelistenBacklog
parameter to a higher value may reduce operation latency as observed by the client by reducing the number of connections which are forced into a backoff state.
-
--maxConns
<number>
¶ The maximum number of simultaneous connections that mongod will accept. This setting has no effect if it is higher than your operating system’s configured maximum connection tracking threshold.
Do not assign too low of a value to this option, or you will encounter errors during normal application operation.
Note
Changed in version 2.6: MongoDB removed the upward limit on the
maxIncomingConnections
setting.
-
--logpath
<path>
¶ Sends all diagnostic logging information to a log file instead of to standard output or to the host’s syslog system. MongoDB creates the log file at the path you specify.
By default, MongoDB will move any existing log file rather than overwrite it. To instead append to the log file, set the
--logappend
option.
-
--syslog
¶
Sends all logging output to the host’s syslog system rather than to standard output or to a log file. , as with
--logpath
.The
--syslog
option is not supported on Windows.Warning
The
syslog
daemon generates timestamps when it logs a message, not when MongoDB issues the message. This can lead to misleading timestamps for log entries, especially when the system is under heavy load. We recommend using the--logpath
option for production systems to ensure accurate timestamps.
-
--syslogFacility
<string>
¶ Default: user
Specifies the facility level used when logging messages to syslog. The value you specify must be supported by your operating system’s implementation of syslog. To use this option, you must enable the
--syslog
option.
-
--logappend
¶
Appends new entries to the end of the existing log file when the mongod instance restarts. Without this option,
mongod
will back up the existing log and create a new file.
-
--logRotate
<string>
¶ Default: rename
New in version 3.0.0.
Determines the behavior for the
logRotate
command. Specify eitherrename
orreopen
:rename
renames the log file.reopen
closes and reopens the log file following the typical Linux/Unix log rotate behavior. Usereopen
when using the Linux/Unix logrotate utility to avoid log loss.If you specify
reopen
, you must also use--logappend
.
If auditing is enabled, the
logRotate
command also rotates the audit log according to the above parameters. For example, if--logRotate
is set torename
, the audit log will also be renamed.
-
--timeStampFormat
<string>
¶ Default: iso8601-local
The time format for timestamps in log messages. Specify one of the following values:
Value Description ctime
Displays timestamps as Wed Dec 31 18:17:54.811
.iso8601-utc
Displays timestamps in Coordinated Universal Time (UTC) in the ISO-8601 format. For example, for New York at the start of the Epoch: 1970-01-01T00:00:00.000Z
iso8601-local
Displays timestamps in local time in the ISO-8601 format. For example, for New York at the start of the Epoch: 1969-12-31T19:00:00.000-0500
-
--traceExceptions
¶
For internal diagnostic use only.
-
--pidfilepath
<path>
¶ Specifies a file location to store the process ID (PID) of the mongod process. The user running the
mongod
ormongos
process must be able to write to this path. If the--pidfilepath
option is not specified, the process does not create a PID file. This option is generally only useful in combination with the--fork
option.Linux
On Linux, PID file management is generally the responsibility of your distro’s init system: usually a service file in the
/etc/init.d
directory, or a systemd unit file registered withsystemctl
. Only use the--pidfilepath
option if you are not using one of these init systems. For more information, please see the respective Installation Guide for your operating system.macOS
On macOS, PID file management is generally handled by
brew
. Only use the--pidfilepath
option if you are not usingbrew
on your macOS system. For more information, please see the respective Installation Guide for your operating system.
-
--keyFile
<file>
¶ Specifies the path to a key file that stores the shared secret that MongoDB instances use to authenticate to each other in a sharded cluster or replica set.
--keyFile
implies--auth
. See Internal Authentication for more information.
-
--setParameter
<options>
¶ Specifies one of the MongoDB parameters described in MongoDB Server Parameters. You can specify multiple
setParameter
fields.
-
--nounixsocket
¶
Disables listening on the UNIX domain socket.
--nounixsocket
applies only to Unix-based systems.The mongod process always listens on the UNIX socket unless one of the following is true:
--nounixsocket
is setnet.bindIp
is not setnet.bindIp
does not specifylocalhost
or its associated IP address
-
--unixSocketPrefix
<path>
¶ Default: /tmp
The path for the UNIX socket.
--unixSocketPrefix
applies only to Unix-based systems.If this option has no value, the mongod process creates a socket with
/tmp
as a prefix. MongoDB creates and listens on a UNIX socket unless one of the following is true:net.unixDomainSocket.enabled
isfalse
--nounixsocket
is setnet.bindIp
is not setnet.bindIp
does not specifylocalhost
or its associated IP address
-
--filePermissions
<path>
¶ Default:
0700
Sets the permission for the UNIX domain socket file.
--filePermissions
applies only to Unix-based systems.
-
--fork
¶
Enables a daemon mode that runs the mongod process in the background. By default mongod does not run as a daemon: typically you will run mongod as a daemon, either by using
--fork
or by using a controlling process that handles the daemonization process (e.g. as withupstart
andsystemd
).Using the
--fork
option requires that you configure log output for the mongod with one of the following:The
--fork
option is not supported on Windows.
-
--auth
¶
Enables authorization to control user’s access to database resources and operations. When authorization is enabled, MongoDB requires all clients to authenticate themselves first in order to determine the access for the client.
Configure users via the mongo shell. If no users exist, the localhost interface will continue to have access to the database until you create the first user.
See Security for more information.
-
--noauth
¶
Disables authentication. Currently the default. Exists for future compatibility and clarity.
-
--transitionToAuth
¶
New in version 3.4: Allows the mongod to accept and create authenticated and non-authenticated connections to and from other
mongod
andmongos
instances in the deployment. Used for performing rolling transition of replica sets or sharded clusters from a no-auth configuration to internal authentication. Requires specifying a internal authentication mechanism such as--keyFile
.For example, if using keyfiles for internal authentication, the mongod creates an authenticated connection with any
mongod
ormongos
in the deployment using a matching keyfile. If the security mechanisms do not match, the mongod utilizes a non-authenticated connection instead.A mongod running with
--transitionToAuth
does not enforce user access controls. Users may connect to your deployment without any access control checks and perform read, write, and administrative operations.Note
A mongod running with internal authentication and without
--transitionToAuth
requires clients to connect using user access controls. Update clients to connect to the mongod using the appropriate user prior to restarting mongod without--transitionToAuth
.
-
--cpu
¶
Forces the mongod process to report the percentage of CPU time in write lock, every four seconds.
-
--sysinfo
¶
Returns diagnostic system information and then exits. The information provides the page size, the number of physical pages, and the number of available physical pages.
-
--noscripting
¶
Disables the scripting engine.
-
--notablescan
¶
Forbids operations that require a collection scan. See
notablescan
for additional information.
-
--shutdown
¶
The
--shutdown
option cleanly and safely terminates the mongod process. When invoking mongod with this option you must set the--dbpath
option either directly or by way of the configuration file and the--config
option.The
--shutdown
option is available only on Linux systems.For additional ways to shut down, see also Stop mongod Processes.
-
--redactClientLogData
¶
New in version 3.4: Available in MongoDB Enterprise only.
A mongod running with
--redactClientLogData
redacts any message accompanying a given log event before logging. This prevents the mongod from writing potentially sensitive data stored on the database to the diagnostic log. Metadata such as error or operation codes, line numbers, and source file names are still visible in the logs.Use
--redactClientLogData
in conjunction with Encryption at Rest and TLS/SSL (Transport Encryption) to assist compliance with regulatory requirements.For example, a MongoDB deployment might store Personally Identifiable Information (PII) in one or more collections. The mongod logs events such as those related to CRUD operations, sharding metadata, etc. It is possible that the mongod may expose PII as a part of these logging operations. A mongod running with
--redactClientLogData
removes any message accompanying these events before being output to the log, effectively removing the PII.Diagnostics on a mongod running with
--redactClientLogData
may be more difficult due to the lack of data related to a log event. See the process logging manual page for an example of the effect of--redactClientLogData
on log output.On a running mongod, use
setParameter
with theredactClientLogData
parameter to configure this setting.
-
--networkMessageCompressors
<string>
¶ Default: snappy
New in version 3.4.
Specifies the default compressor(s) to use for communication between this mongod instance and:
- other members of the deployment if the instance is part of a replica set or a sharded cluster
- a
mongo
shell - drivers that support the
OP_COMPRESSED
message format.
MongoDB supports the following compressors:
In versions 3.6 and 4.0,
mongod
andmongos
enable network compression by default withsnappy
as the compressor.To disable network compression, set the value to
disabled
.Important
Messages are compressed when both parties enable network compression. Otherwise, messages between the parties are uncompressed.
If you specify multiple compressors, then the order in which you list the compressors matter as well as the communication initiator. For example, if a
mongo
shell specifies the following network compressorszlib,snappy
and themongod
specifiessnappy,zlib
, messages betweenmongo
shell andmongod
useszlib
.If the parties do not share at least one common compressor, messages between the parties are uncompressed. For example, if a
mongo
shell specifies the network compressorzlib
andmongod
specifiessnappy
, messages betweenmongo
shell andmongod
are not compressed.
-
--timeZoneInfo
<path>
¶ The full path from which to load the time zone database. If this option is not provided, then MongoDB will use its built-in time zone database.
The configuration file included with Linux and macOS packages sets the time zone database path to
/usr/share/zoneinfo
by default.The built-in time zone database is a copy of the Olson/IANA time zone database. It is updated along with MongoDB releases, but the time zone database release cycle differs from the MongoDB release cycle. The most recent release of the time zone database is available on our download site.
Warning
MongoDB uses the third party timelib library to provide accurate conversions between timezones. Due to a recent update,
timelib
could create inaccurate time zone conversions in older versions of MongoDB.To explicitly link to the time zone database in versions of MongoDB prior to 4.0.25, download the time zone database. and use the
timeZoneInfo
parameter.See also
-
--serviceExecutor
<string>
¶ Default: synchronous
New in version 3.6.
Determines the threading and execution model mongod uses to execute client requests. The
--serviceExecutor
option accepts one of the following values:Value Description synchronous
The mongod uses synchronous networking and manages its networking thread pool on a per connection basis. Previous versions of MongoDB managed threads in this way. adaptive
The mongod uses the new experimental asynchronous networking mode with an adaptive thread pool which manages threads on a per request basis. This mode should have more consistent performance and use less resources when there are more inactive connections than database requests.
Free Monitoring¶
New in version 4.0.
-
--enableFreeMonitoring
<runtime|on|off>
¶ New in version 4.0: Available for MongoDB Community Edition.
Enables or disables free MongoDB Cloud monitoring.
--enableFreeMonitoring
accepts the following values:runtime
Default. You can enable or disable free monitoring during runtime.
To enable or disable free monitoring during runtime, see
db.enableFreeMonitoring()
anddb.disableFreeMonitoring()
.To enable or disable free monitoring during runtime when running with access control, users must have required privileges. See
db.enableFreeMonitoring()
anddb.disableFreeMonitoring()
for details.on
Enables free monitoring at startup; i.e. registers for free monitoring. When enabled at startup, you cannot disable free monitoring during runtime. off
Disables free monitoring at startup, regardless of whether you have previously registered for free monitoring. When disabled at startup, you cannot enable free monitoring during runtime. Once enabled, the free monitoring state remains enabled until explicitly disabled. That is, you do not need to re-enable each time you start the server.
For the corresponding configuration file setting, see
cloud.monitoring.free.state
.
-
--freeMonitoringTag
<string>
¶ New in version 4.0: Available for MongoDB Community Edition.
Optional tag to describe environment context. The tag can be sent as part of the free MongoDB Cloud monitoring registration at start up.
For the corresponding configuration file setting, see
cloud.monitoring.free.tags
.
LDAP Authentication or Authorization Options¶
-
--ldapServers
<host1>:<port>,<host2>:<port>,...,<hostN>:<port>
¶ New in version 3.4: Available in MongoDB Enterprise only.
The LDAP server against which the mongod authenticates users or determines what actions a user is authorized to perform on a given database. If the LDAP server specified has any replicated instances, you may specify the host and port of each replicated server in a comma-delimited list.
If your LDAP infrastructure partitions the LDAP directory over multiple LDAP servers, specify one LDAP server or any of its replicated instances to
--ldapServers
. MongoDB supports following LDAP referrals as defined in RFC 4511 4.1.10. Do not use--ldapServers
for listing every LDAP server in your infrastructure.This setting can be configured on a running mongod using
setParameter
.If unset, mongod cannot use LDAP authentication or authorization.
-
--ldapValidateLDAPServerConfig
<boolean>
¶ Available in MongoDB Enterprise
A flag that determines if the
mongod
instance checks the availability of theLDAP server(s)
as part of its startup:
-
--ldapQueryUser
<string>
¶ New in version 3.4: Available in MongoDB Enterprise only.
The identity with which mongod binds as, when connecting to or performing queries on an LDAP server.
Only required if any of the following are true:
- Using LDAP authorization.
- Using an LDAP query for
username transformation
. - The LDAP server disallows anonymous binds
You must use
--ldapQueryUser
with--ldapQueryPassword
.If unset, mongod will not attempt to bind to the LDAP server.
This setting can be configured on a running mongod using
setParameter
.Note
Windows MongoDB deployments can use
--ldapBindWithOSDefaults
instead of--ldapQueryUser
and--ldapQueryPassword
. You cannot specify both--ldapQueryUser
and--ldapBindWithOSDefaults
at the same time.
-
--ldapQueryPassword
<string>
¶ New in version 3.4: Available in MongoDB Enterprise only.
The password used to bind to an LDAP server when using
--ldapQueryUser
. You must use--ldapQueryPassword
with--ldapQueryUser
.If unset, mongod will not attempt to bind to the LDAP server.
This setting can be configured on a running mongod using
setParameter
.Note
Windows MongoDB deployments can use
--ldapBindWithOSDefaults
instead of--ldapQueryPassword
and--ldapQueryPassword
. You cannot specify both--ldapQueryPassword
and--ldapBindWithOSDefaults
at the same time.
-
--ldapBindWithOSDefaults
<bool>
¶ Default: false
New in version 3.4: Available in MongoDB Enterprise for the Windows platform only.
Allows mongod to authenticate, or bind, using your Windows login credentials when connecting to the LDAP server.
Only required if:
- Using LDAP authorization.
- Using an LDAP query for
username transformation
. - The LDAP server disallows anonymous binds
Use
--ldapBindWithOSDefaults
to replace--ldapQueryUser
and--ldapQueryPassword
.
-
--ldapBindMethod
<string>
¶ Default: simple
New in version 3.4: Available in MongoDB Enterprise only.
The method mongod uses to authenticate to an LDAP server. Use with
--ldapQueryUser
and--ldapQueryPassword
to connect to the LDAP server.--ldapBindMethod
supports the following values:simple
- mongod uses simple authentication.sasl
- mongod uses SASL protocol for authentication
If you specify
sasl
, you can configure the available SASL mechanisms using--ldapBindSaslMechanisms
. mongod defaults to usingDIGEST-MD5
mechanism.
-
--ldapBindSaslMechanisms
<string>
¶ Default: DIGEST-MD5
New in version 3.4: Available in MongoDB Enterprise only.
A comma-separated list of SASL mechanisms mongod can use when authenticating to the LDAP server. The mongod and the LDAP server must agree on at least one mechanism. The mongod dynamically loads any SASL mechanism libraries installed on the host machine at runtime.
Install and configure the appropriate libraries for the selected SASL mechanism(s) on both the mongod host and the remote LDAP server host. Your operating system may include certain SASL libraries by default. Defer to the documentation associated with each SASL mechanism for guidance on installation and configuration.
If using the
GSSAPI
SASL mechanism for use with Kerberos Authentication, verify the following for the mongod host machine:Linux
- The
KRB5_CLIENT_KTNAME
environment variable resolves to the name of the client Linux Keytab Files for the host machine. For more on Kerberos environment variables, please defer to the Kerberos documentation. - The client keytab includes a User Principal for the mongod to use when connecting to the LDAP server and execute LDAP queries.
- The
Windows
- If connecting to an Active Directory server, the Windows
Kerberos configuration automatically generates a
Ticket-Granting-Ticket
when the user logs onto the system. Set
--ldapBindWithOSDefaults
totrue
to allow mongod to use the generated credentials when connecting to the Active Directory server and execute queries.
Set
--ldapBindMethod
tosasl
to use this option.Note
For a complete list of SASL mechanisms see the IANA listing. Defer to the documentation for your LDAP or Active Directory service for identifying the SASL mechanisms compatible with the service.
MongoDB is not a source of SASL mechanism libraries, nor is the MongoDB documentation a definitive source for installing or configuring any given SASL mechanism. For documentation and support, defer to the SASL mechanism library vendor or owner.
For more information on SASL, defer to the following resources:
- For Linux, please see the Cyrus SASL documentation.
- For Windows, please see the Windows SASL documentation.
-
--ldapTransportSecurity
<string>
¶ Default: tls
New in version 3.4: Available in MongoDB Enterprise only.
By default, mongod creates a TLS/SSL secured connection to the LDAP server.
For Linux deployments, you must configure the appropriate TLS Options in
/etc/openldap/ldap.conf
file. Your operating system’s package manager creates this file as part of the MongoDB Enterprise installation, via thelibldap
dependency. See the documentation forTLS Options
in the ldap.conf OpenLDAP documentation for more complete instructions.For Windows deployment, you must add the LDAP server CA certificates to the Windows certificate management tool. The exact name and functionality of the tool may vary depending on operating system version. Please see the documentation for your version of Windows for more information on certificate management.
Set
--ldapTransportSecurity
tonone
to disable TLS/SSL between mongod and the LDAP server.Warning
Setting
--ldapTransportSecurity
tonone
transmits plaintext information and possibly credentials between mongod and the LDAP server.
-
--ldapTimeoutMS
<long>
¶ Default: 10000
New in version 3.4: Available in MongoDB Enterprise only.
The amount of time in milliseconds mongod should wait for an LDAP server to respond to a request.
Increasing the value of
--ldapTimeoutMS
may prevent connection failure between the MongoDB server and the LDAP server, if the source of the failure is a connection timeout. Decreasing the value of--ldapTimeoutMS
reduces the time MongoDB waits for a response from the LDAP server.This setting can be configured on a running mongod using
setParameter
.
-
--ldapUserToDNMapping
<string>
¶ New in version 3.4: Available in MongoDB Enterprise only.
Maps the username provided to mongod for authentication to a LDAP Distinguished Name (DN). You may need to use
--ldapUserToDNMapping
to transform a username into an LDAP DN in the following scenarios:- Performing LDAP authentication with simple LDAP binding, where users authenticate to MongoDB with usernames that are not full LDAP DNs.
- Using an
LDAP authorization query template
that requires a DN. - Transforming the usernames of clients authenticating to Mongo DB using different authentication mechanisms (e.g. x.509, kerberos) to a full LDAP DN for authorization.
--ldapUserToDNMapping
expects a quote-enclosed JSON-string representing an ordered array of documents. Each document contains a regular expressionmatch
and either asubstitution
orldapQuery
template used for transforming the incoming username.Each document in the array has the following form:
Field Description Example match
An ECMAScript-formatted regular expression (regex) to match against a provided username. Each parenthesis-enclosed section represents a regex capture group used by substitution
orldapQuery
."(.+)ENGINEERING"
"(.+)DBA"
substitution
An LDAP distinguished name (DN) formatting template that converts the authentication name matched by the
match
regex into a LDAP DN. Each curly bracket-enclosed numeric value is replaced by the corresponding regex capture group extracted from the authentication username via thematch
regex.The result of the substitution must be an RFC4514 escaped string.
"cn={0},ou=engineering, dc=example,dc=com"
ldapQuery
A LDAP query formatting template that inserts the authentication name matched by the match
regex into an LDAP query URI encoded respecting RFC4515 and RFC4516. Each curly bracket-enclosed numeric value is replaced by the corresponding regex capture group extracted from the authentication username via thematch
expression. mongod executes the query against the LDAP server to retrieve the LDAP DN for the authenticated user. mongod requires exactly one returned result for the transformation to be successful, or mongod skips this transformation."ou=engineering,dc=example, dc=com??one?(user={0})"
Note
An explanation of RFC4514, RFC4515, RFC4516, or LDAP queries is out of scope for the MongoDB Documentation. Please review the RFC directly or use your preferred LDAP resource.
For each document in the array, you must use either
substitution
orldapQuery
. You cannot specify both in the same document.When performing authentication or authorization, mongod steps through each document in the array in the given order, checking the authentication username against the
match
filter. If a match is found, mongod applies the transformation and uses the output for authenticating the user. mongod does not check the remaining documents in the array.If the given document does not match the provided authentication name, or the transformation described by the document fails, mongod continues through the list of documents to find additional matches. If no matches are found in any document, mongod returns an error.
Example
The following shows two transformation documents. The first document matches against any string ending in
@ENGINEERING
, placing anything preceeding the suffix into a regex capture group. The second document matches against any string ending in@DBA
, placing anything preceeding the suffix into a regex capture group.Important
You must pass the array to
--ldapUserToDNMapping
as a string.A user with username
alice@ENGINEERING.EXAMPLE.COM
matches the first document. The regex capture group{0}
corresponds to the stringalice
. The resulting output is the DN"cn=alice,ou=engineering,dc=example,dc=com"
.A user with username
bob@DBA.EXAMPLE.COM
matches the second document. The regex capture group{0}
corresponds to the stringbob
. The resulting output is the LDAP query"ou=dba,dc=example,dc=com??one?(user=bob)"
. mongod executes this query against the LDAP server, returning the result"cn=bob,ou=dba,dc=example,dc=com"
.If
--ldapUserToDNMapping
is unset, mongod applies no transformations to the username when attempting to authenticate or authorize a user against the LDAP server.This setting can be configured on a running mongod using the
setParameter
database command.
-
--ldapAuthzQueryTemplate
<string>
¶ New in version 3.4: Available in MongoDB Enterprise only.
A relative LDAP query URL formatted conforming to RFC4515 and RFC4516 that mongod executes to obtain the LDAP groups to which the authenticated user belongs to. The query is relative to the host or hosts specified in
--ldapServers
.Use the
{USER}
placeholder in the URL to substitute the authenticated username, or the transformed username if ausername mapping
is specified.When constructing the query URL, ensure that the order of LDAP parameters respects RFC4516:
If your query includes an attribute, mongod assumes that the query retrieves a the DNs which this entity is member of.
If your query does not include an attribute, mongod assumes the query retrieves all entities which the user is member of.
For each LDAP DN returned by the query, mongod assigns the authorized user a corresponding role on the
admin
database. If a role on the on theadmin
database exactly matches the DN, mongod grants the user the roles and privileges assigned to that role. See thedb.createRole()
method for more information on creating roles.Example
This LDAP query returns any groups listed in the LDAP user object’s
memberOf
attribute.Your LDAP configuration may not include the
memberOf
attribute as part of the user schema, may possess a different attribute for reporting group membership, or may not track group membership through attributes. Configure your query with respect to your own unique LDAP configuration.If unset, mongod cannot authorize users using LDAP.
This setting can be configured on a running mongod using the
setParameter
database command.
Storage Options¶
-
--storageEngine
string
¶ Default:
wiredTiger
Changed in version 4.0: MongoDB deprecates the MMAPv1 storage engine.
Specifies the storage engine for the mongod database. Available values include:
Value Description wiredTiger
To specify the WiredTiger Storage Engine. inMemory
To specify the In-Memory Storage Engine.
New in version 3.2: Available in MongoDB Enterprise only.
mmapv1
(Deprecated in MongoDB 4.0)To specify the MMAPv1 Storage Engine. If you attempt to start a mongod with a
--dbpath
that contains data files produced by a storage engine other than the one specified by--storageEngine
, mongod will refuse to start.
-
--dbpath
<path>
¶ Default:
/data/db
on Linux and macOS,\data\db
on WindowsThe directory where the mongod instance stores its data.
If using the default configuration file included with a package manager installation of MongoDB, the corresponding
storage.dbPath
setting uses a different default.Changed in version 3.0: The files in
--dbpath
must correspond to the storage engine specified in--storageEngine
. If the data files do not correspond to--storageEngine
, mongod will refuse to start.
-
--directoryperdb
¶
Uses a separate directory to store data for each database. The directories are under the
--dbpath
directory, and each subdirectory name corresponds to the database name.Changed in version 3.0: To change the
--directoryperdb
option for existing deployments, you must restart themongod
instances with the new--directoryperdb
value and a new data directory (--dbpath <new path>
), and then repopulate the data.- For standalone instances, you can use
mongodump
on the existing instance, stop the instance, restart with the new--directoryperdb
value and a new data directory, and usemongorestore
to populate the new data directory. - For replica sets, you can update in a rolling manner by stopping
a secondary member, restart with the new
--directoryperdb
value and a new data directory, and use initial sync to populate the new data directory. To update all members, start with the secondary members first. Then step down the primary, and update the stepped-down member.
Not available for
mongod
instances that use the in-memory storage engine.- For standalone instances, you can use
-
--noIndexBuildRetry
¶
Changed in version 4.0:
--noIndexBuildRetry
cannot be used in conjunction with--replSet
; i.e., you cannot use--noIndexBuildRetry
for amongod
instance that is part of a replica set.Stops the mongod standalone instance from rebuilding incomplete indexes on the next start up. This applies in cases where the mongod restarts after it has shut down or stopped in the middle of an index build. In such cases, the mongod always removes any incomplete indexes, and then also, by default, attempts to rebuild them. To stop the mongod from rebuilding incomplete indexes on start up, include this option on the command-line.
The
--noIndexBuildRetry
only applies to standalones.Not available for
mongod
instances that use the in-memory storage engine.
-
--noprealloc
¶
Only available for the MMAPv1 storage engine.
Deprecated since version 2.6: By default, MongoDB does not preallocate data files. The option exists for compatibility.
Disables the preallocation of data files.
-
--nssize
<value>
¶ Default: 16
Only available for the MMAPv1 storage engine.
Specifies the default size for namespace files, which are files that end in
.ns
. Each collection and index counts as a namespace.Use this setting to control size for newly created namespace files. This option has no impact on existing files. The maximum size for a namespace file is 2047 megabytes. The default value of 16 megabytes provides for approximately 24,000 namespaces.
-
--quota
¶
Only available for the MMAPv1 storage engine.
Enables a maximum limit for the number data files each database can have. When running with the
--quota
option, MongoDB has a maximum of 8 data files per database. Adjust the quota with--quotaFiles
.
-
--quotaFiles
<number>
¶ Default: 8
Only available for the MMAPv1 storage engine.
Modifies the limit on the number of data files per database.
--quotaFiles
option requires that you set--quota
.
-
--smallfiles
¶
Only available for the MMAPv1 storage engine.
Sets MongoDB to use a smaller default file size. The
--smallfiles
option reduces the initial size for data files and limits the maximum size to 512 megabytes.--smallfiles
also reduces the size of each journal file from 1 gigabyte to 128 megabytes. Use--smallfiles
if you have a large number of databases that each holds a small quantity of data.The
--smallfiles
option can lead the mongod instance to create a large number of files, which can affect performance for larger databases.
-
--syncdelay
<value>
¶ Default: 60
Controls how much time can pass before MongoDB flushes data to the data files via an fsync operation.
Do not set this value on production systems. In almost every situation, you should use the default setting.
Warning
If you set
--syncdelay
to0
, MongoDB will not sync the memory mapped files to disk.The mongod process writes data very quickly to the journal and lazily to the data files.
--syncdelay
has no effect on thejournal
files or journaling, but if--syncdelay
is set to0
the journal will eventually consume all available disk space. If you set--syncdelay
to0
for testing purposes, you should also set--nojournal
totrue
.The
serverStatus
command reports the background flush thread’s status via thebackgroundFlushing
field.Not available for
mongod
instances that use the in-memory storage engine.
-
--upgrade
¶
Upgrades the on-disk data format of the files specified by the
--dbpath
to the latest version, if needed.This option only affects the operation of the mongod if the data files are in an old format.
In most cases you should not set this value, so you can exercise the most control over your upgrade process. See the MongoDB release notes for more information about the upgrade process.
-
--repair
¶
Changed in version 4.0.3.
Runs a repair routine on all databases for a
mongod
instance. The operation attempts to salvage corrupt data as well as rebuilds all the indexes. The operation discards any corrupt data that cannot be salvaged.Tip
If you are running with journaling enabled, there is almost never any need to run repair since the server can use the journal files to restore the data files to a clean state automatically. However, you may need to run repair in cases where you need to recover from a disk-level data corruption.
Warning
- Before using
--repair
, make a backup copy of thedbpath
directory. - Avoid running
--repair
against a replica set:- To repair a replica set member, if you have an intact copy of your data available (e.g. a recent backup or an intact member of the replica set), restore from that intact copy instead(see Resync a Member of a Replica Set).
- If you do choose to run
mongod --repair
against a replica set member and the operation modifies the data or the metadata, you must still perform a full resync in order for the member to rejoin the replica set.
- Only use
mongod --repair
(and the related operationsrepairDatabase
command anddb.repairDatabase()
method) if you have no other options. The operations remove and do not save any corrupt data during the repair process. - If repair fails to complete for any reason, you must restart the
instance using the
--repair
option.
For MMAPv1 storage engine, see also
--repairpath
.- Before using
-
--repairpath
<path>
¶ Default: A
_tmp_repairDatabase_<num>
directory under thedbPath
.Only available for the MMAPv1 storage engine.
Specifies a working directory that MongoDB will use during the
--repair
operation. When--repair
completes, the--repairpath
directory is empty, anddbPath
contains the repaired files.The
--repairpath
must be within thedbPath
. You can specify a symlink to--repairpath
to use a path on a different file system.
-
--journal
¶
Enables the durability journal to ensure data files remain valid and recoverable. This option applies only when you specify the
--dbpath
option. mongod enables journaling by default.Not available for
mongod
instances that use the in-memory storage engine.If any voting member of a replica set uses the in-memory storage engine, you must set
writeConcernMajorityJournalDefault
tofalse
.Starting in version 4.0.13 (and 3.6.14), if a replica set member uses the in-memory storage engine (voting or non-voting) but the replica set has
writeConcernMajorityJournalDefault
set to true, the replica set member logs a startup warning.
-
--nojournal
¶
Disables journaling. mongod enables journaling by default.
Not available for
mongod
instances that use the in-memory storage engine.Starting in MongoDB 4.0, you cannot specify
--nojournal
option orstorage.journal.enabled: false
for replica set members that use the WiredTiger storage engine.
-
--journalOptions
<arguments>
¶ Only available for the MMAPv1 storage engine.
Provides functionality for testing. Not for general use, and will affect data file integrity in the case of abnormal system shutdown.
Not available for
mongod
instances that use the in-memory storage engine.
-
--journalCommitInterval
<value>
¶ Default: 100 or 30
Changed in version 3.2.
The maximum amount of time in milliseconds that the mongod process allows between journal operations. Values can range from 1 to 500 milliseconds. Lower values increase the durability of the journal, at the expense of disk performance. The default journal commit interval is 100 milliseconds.
On MMAPv1, if the journal is on a different block device (e.g. physical volume, RAID device, or LVM volume) than the data files, the default journal commit interval is 30 milliseconds. Additionally, on MMAPv1, when a write operation with
j:true
is pending, mongod will reducecommitIntervalMs
to a third of the set value.On WiredTiger, the default journal commit interval is 100 milliseconds. Additionally, a write that includes or implies
j:true
will cause an immediate sync of the journal. For details or additional conditions that affect the frequency of the sync for WiredTiger, see Journaling Process.Not available for
mongod
instances that use the in-memory storage engine.
WiredTiger Options¶
-
--wiredTigerCacheSizeGB
<float>
¶ Defines the maximum size of the internal cache that WiredTiger will use for all data. The memory consumed by an index build (see
maxIndexBuildMemoryUsageMegabytes
) is separate from the WiredTiger cache memory. Starting in MongoDB 3.4, the values can range from 0.25 GB to 10000 GB and can be a float.Starting in MongoDB 3.4, the default WiredTiger internal cache size is the larger of either:
- 50% of (RAM - 1 GB), or
- 256 MB.
For example, on a system with a total of 4GB of RAM the WiredTiger cache will use 1.5GB of RAM (
0.5 * (4 GB - 1 GB) = 1.5 GB
). Conversely, a system with a total of 1.25 GB of RAM will allocate 256 MB to the WiredTiger cache because that is more than half of the total RAM minus one gigabyte (0.5 * (1.25 GB - 1 GB) = 128 MB < 256 MB
).Note
In some instances, such as when running in a container, the database can have memory constraints that are lower than the total system memory. In such instances, this memory limit, rather than the total system memory, is used as the maximum RAM available.
To see the memory limit, see
hostInfo.system.memLimitMB
.Avoid increasing the WiredTiger internal cache size above its default value.
With WiredTiger, MongoDB utilizes both the WiredTiger internal cache and the filesystem cache.
Via the filesystem cache, MongoDB automatically uses all free memory that is not used by the WiredTiger cache or by other processes.
Note
The
--wiredTigerCacheSizeGB
limits the size of the WiredTiger internal cache. The operating system will use the available free memory for filesystem cache, which allows the compressed MongoDB data files to stay in memory. In addition, the operating system will use any free RAM to buffer file system blocks and file system cache.To accommodate the additional consumers of RAM, you may have to decrease WiredTiger internal cache size.
The default WiredTiger internal cache size value assumes that there is a single
mongod
instance per machine. If a single machine contains multiple MongoDB instances, then you should decrease the setting to accommodate the othermongod
instances.If you run
mongod
in a container (e.g.lxc
,cgroups
, Docker, etc.) that does not have access to all of the RAM available in a system, you must set--wiredTigerCacheSizeGB
to a value less than the amount of RAM available in the container. The exact amount depends on the other processes running in the container. SeememLimitMB
.
-
--wiredTigerMaxCacheOverflowFileSizeGB
<float>
¶ Specifies the maximum size (in GB) for the “lookaside (or cache overflow) table” file
WiredTigerLAS.wt
.The setting can accept the following values:
Value Description 0
The default value. If set to 0
, the file size is unbounded.number >= 0.1 The maximum size (in GB). If the WiredTigerLAS.wt
file exceeds this size,mongod
exits with a fatal assertion. You can clear theWiredTigerLAS.wt
file and restartmongod
.To change the maximum size during runtime, use the
wiredTigerMaxCacheOverflowSizeGB
parameter.Available in 4.0-series starting in 4.0.12
-
--wiredTigerJournalCompressor
<compressor>
¶ Default: snappy
New in version 3.0.0.
Specifies the type of compression to use to compress WiredTiger journal data.
Available compressors are:
For details on changing the journal compressor, see Change WiredTiger Journal Compressor.
-
--wiredTigerDirectoryForIndexes
¶
New in version 3.0.0.
When you start mongod with
--wiredTigerDirectoryForIndexes
, mongod stores indexes and collections in separate subdirectories under the data (i.e.--dbpath
) directory. Specifically, mongod stores the indexes in a subdirectory namedindex
and the collection data in a subdirectory namedcollection
.By using a symbolic link, you can specify a different location for the indexes. Specifically, when
mongod
instance is not running, move theindex
subdirectory to the destination and create a symbolic link namedindex
under the data directory to the new destination.
-
--wiredTigerCollectionBlockCompressor
<compressor>
¶ Default: snappy
New in version 3.0.0.
Specifies the default type of compression to use to compress collection data. You can override this on a per-collection basis when creating collections.
Available compressors are:
--wiredTigerCollectionBlockCompressor
affects all collections created. If you change the value of--wiredTigerCollectionBlockCompressor
on an existing MongoDB deployment, all new collections will use the specified compressor. Existing collections will continue to use the compressor specified when they were created, or the default compressor at that time.
-
--wiredTigerIndexPrefixCompression
<boolean>
¶ Default: true
New in version 3.0.0.
Enables or disables prefix compression for index data.
Specify
true
for--wiredTigerIndexPrefixCompression
to enable prefix compression for index data, orfalse
to disable prefix compression for index data.The
--wiredTigerIndexPrefixCompression
setting affects all indexes created. If you change the value of--wiredTigerIndexPrefixCompression
on an existing MongoDB deployment, all new indexes will use prefix compression. Existing indexes are not affected.
Replication Options¶
-
--replSet
<setname>
¶ Configures replication. Specify a replica set name as an argument to this set. All hosts in the replica set must have the same set name.
Starting in MongoDB 4.0,
--replSet
cannot be used in conjunction with--noIndexBuildRetry
.- For the WiredTiger storage engine,
--replSet
cannot be used in conjunction with--nojournal
.
If your application connects to more than one replica set, each set must have a distinct name. Some drivers group replica set connections by replica set name.
-
--oplogSize
<value>
¶ Specifies a maximum size in megabytes for the replication operation log (i.e., the oplog).
Note
Starting in MongoDB 4.0, the oplog can grow past its configured size limit to avoid deleting the
majority commit point
.By default, the mongod process creates an oplog based on the maximum amount of space available. For 64-bit systems, the oplog is typically 5% of available disk space.
Once the mongod has created the oplog for the first time, changing the
--oplogSize
option will not affect the size of the oplog.To change the oplog size of a running replica set member, use the
replSetResizeOplog
administrative command.replSetResizeOplog
enables you to resize the oplog dynamically without restarting themongod
process.See Oplog Size for more information.
-
--replIndexPrefetch
¶
Default: all
Storage Engine Specific Feature
--replIndexPrefetch
is only available with themmapv1
storage engine.Determines which indexes secondary members of a replica set load into memory before applying operations from the oplog. By default secondaries load all indexes related to an operation into memory before applying operations from the oplog.
Set this option to one of the following:
Value Description none
Secondaries do not load indexes into memory. all
Secondaries load all indexes related to an operation. _id_only
Secondaries load no additional indexes into memory beyond the already existing _id
index.
-
--enableMajorityReadConcern
¶
Default: true
Starting in MongoDB 3.6, MongoDB enables support for
"majority"
read concern by default.For MongoDB 4.0.3+ and 3.6.1+, you can disable read concern
"majority"
to prevent the storage cache pressure from immobilizing a deployment with a three-member primary-secondary-arbiter (PSA) architecture. For more information about disabling read concern"majority"
, see Disable Read Concern Majority.To disable, set
--enableMajorityReadConcern
to false.Important
In general, avoid disabling
"majority"
read concern unless necessary. However, if you have a three-member replica set with a primary-secondary-arbiter (PSA) architecture or a sharded cluster with a three-member PSA shards, disable to prevent the storage cache pressure from immobilizing the deployment.Disabling
"majority"
read concern disables support for Change Streams.Disabling
"majority"
does not affect multi-document transactions; i.e. you can specify read concern “majority” for multi-document transactions even if read concern “majority” is disabled.--enableMajorityReadConcern
has no effect for MongoDB versions: 4.0.0, 4.0.1, 4.0.2, 3.6.0.
Sharded Cluster Options¶
-
--configsvr
¶
Required if starting a config server.
Declares that this mongod instance serves as the config server of a sharded cluster. When running with this option, clients (i.e. other cluster components) cannot write data to any database other than
config
andadmin
. The default port for a mongod with this option is27019
and the default--dbpath
directory is/data/configdb
, unless specified.Important
Starting in 3.4, you must deploy config servers as a replica set. The use of the deprecated mirrored
mongod
instances as config servers (SCCC) is no longer supported.The replica set config servers (CSRS) must run the WiredTiger storage engine.
The
--configsvr
option creates a local oplog.Do not use the
--configsvr
option with--shardsvr
. Config servers cannot be a shard server.Do not use the
--configsvr
with theskipShardingConfigurationChecks
parameter. That is, if you are temporarily starting themongod
as a standalone for maintenance operations, include the parameterskipShardingConfigurationChecks
and exclude--configsvr
. Once maintenance has completed, remove theskipShardingConfigurationChecks
parameter and restart with--configsvr
.
-
--configsvrMode
<string>
¶ Available in MongoDB 3.2 version only
If set to
sccc
, indicates that the config servers are deployed as three mirroredmongod
instances, even if one or more config servers is also a member of a replica set.configsvrMode
only accepts the valuesccc
.If unset, config servers running as replica sets expect to use the “config server replica set” protocol for writing to config servers, rather than the “mirrored mongod” write protocol.
-
--shardsvr
¶
Required if starting a shard server.
Configures this mongod instance as a shard in a sharded cluster. The default port for these instances is
27018
.Important
Starting in MongoDB 3.6, you must deploy shards as replica sets. See the
--replSet
option to deploy mongod as part of a replica set.Do not use the
--shardsvr
with theskipShardingConfigurationChecks
parameter. That is, if you are temporarily starting themongod
as a standalone for maintenance operations, include the parameterskipShardingConfigurationChecks
and exclude--shardsvr
. Once maintenance has completed, remove theskipShardingConfigurationChecks
parameter and restart with--shardsvr
.
-
--moveParanoia
¶
If specified, during chunk migration, a shard saves, to the
moveChunk
directory of the--dbpath
, all documents migrated from that shard.MongoDB does not automatically delete the data saved in the
moveChunk
directory.
-
--noMoveParanoia
¶
Changed in version 3.2: Starting in 3.2, MongoDB uses
--noMoveParanoia
as the default.During chunk migration, a shard does not save documents migrated from the shard.
TLS/SSL Options¶
See
Configure mongod and mongos for TLS/SSL for full documentation of MongoDB’s support.
-
--sslOnNormalPorts
¶
Deprecated since version 2.6: Use
--sslMode requireSSL
instead.Enables TLS/SSL for mongod.
With
--sslOnNormalPorts
, a mongod requires TLS/SSL encryption for all connections on the default MongoDB port, or the port specified by--port
. By default,--sslOnNormalPorts
is disabled.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslMode
<mode>
¶ New in version 2.6.
Enables TLS/SSL or mixed TLS/SSL used for all network connections. The argument to the
--sslMode
option can be one of the following:Value Description disabled
The server does not use TLS/SSL. allowSSL
Connections between servers do not use TLS/SSL. For incoming connections, the server accepts both TLS/SSL and non-TLS/non-SSL. preferSSL
Connections between servers use TLS/SSL. For incoming connections, the server accepts both TLS/SSL and non-TLS/non-SSL. requireSSL
The server uses and accepts only TLS/SSL encrypted connections. Starting in version 3.4, if
--sslCAFile
orssl.CAFile
is not specified and you are not using x.509 authentication, the system-wide CA certificate store will be used when connecting to an TLS/SSL-enabled server.If using x.509 authentication,
--sslCAFile
orssl.CAFile
must be specified unless using--sslCertificateSelector
.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslPEMKeyFile
<filename>
¶ Specifies the
.pem
file that contains both the TLS/SSL certificate and key.Changed in version 4.0: Starting with MongoDB 4.0 on macOS or Windows, you can use the
--sslCertificateSelector
option to specify a certificate from the operating system’s secure certificate store instead of a PEM key file.--sslPEMKeyFile
and--sslCertificateSelector
options are mutually exclusive. You can only specify one.On Linux/BSD, you must specify
--sslPEMKeyFile
when TLS/SSL is enabled.On Windows or macOS, you must specify either
--sslPEMKeyFile
or--sslCertificateSelector
when TLS/SSL is enabled.Important
For Windows only, MongoDB 4.0 and later do not support encrypted PEM files. The
mongod
fails to start if it encounters an encrypted PEM file. To securely store and access a certificate for use with TLS/SSL on Windows, use--sslCertificateSelector
.
For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslPEMKeyPassword
<value>
¶ Specifies the password to de-crypt the certificate-key file (i.e.
--sslPEMKeyFile
). Use the--sslPEMKeyPassword
option only if the certificate-key file is encrypted. In all cases, the mongod will redact the password from all logging and reporting output.Starting in MongoDB 4.0:
- On Linux/BSD, if the private key in the PEM file is encrypted and
you do not specify the
--sslPEMKeyPassword
option, MongoDB will prompt for a passphrase. See TLS/SSL Certificate Passphrase. - On macOS, if the private key in the PEM file is
encrypted, you must explicitly specify the
--sslPEMKeyPassword
option. Alternatively, you can use a certificate from the secure system store (see--sslCertificateSelector
) instead of a PEM key file or use an unencrypted PEM file. - On Windows, MongoDB does not support encrypted certificates.
The
mongod
fails if it encounters an encrypted PEM file. Use--sslCertificateSelector
instead.
For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
- On Linux/BSD, if the private key in the PEM file is encrypted and
you do not specify the
-
--clusterAuthMode
<option>
¶ Default: keyFile
New in version 2.6.
The authentication mode used for cluster authentication. If you use internal x.509 authentication, specify so here. This option can have one of the following values:
Value Description keyFile
Use a keyfile for authentication. Accept only keyfiles. sendKeyFile
For rolling upgrade purposes. Send a keyfile for authentication but can accept both keyfiles and x.509 certificates. sendX509
For rolling upgrade purposes. Send the x.509 certificate for authentication but can accept both keyfiles and x.509 certificates. x509
Recommended. Send the x.509 certificate for authentication and accept only x.509 certificates. Starting in version 3.4, if
--sslCAFile
orssl.CAFile
is not specified and you are not using x.509 authentication, the system-wide CA certificate store will be used when connecting to an TLS/SSL-enabled server.If using x.509 authentication,
--sslCAFile
orssl.CAFile
must be specified unless using--sslCertificateSelector
.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslClusterFile
<filename>
¶ Specifies the
.pem
file that contains the x.509 certificate-key file for membership authentication for the cluster or replica set.Changed in version 4.0: Starting with MongoDB 4.0 on macOS or Windows, you can use the
--sslClusterCertificateSelector
option to specify a certificate from the operating system’s secure certificate store instead of a PEM key file.--sslClusterFile
and--sslClusterCertificateSelector
options are mutually exclusive. You can only specify one.If
--sslClusterFile
does not specify the.pem
file for internal cluster authentication or the alternative--sslClusterCertificateSelector
, the cluster uses the.pem
file specified in the--sslPEMKeyFile
option or the certificate returned by the--sslCertificateSelector
.If using x.509 authentication,
--sslCAFile
orssl.CAFile
must be specified unless using--sslCertificateSelector
.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
Important
For Windows only, MongoDB 4.0 and later do not support encrypted PEM files. The
mongod
fails to start if it encounters an encrypted PEM file. To securely store and access a certificate for use with membership authentication on Windows, use--sslClusterCertificateSelector
.
-
--sslCertificateSelector
<parameter>=<value>
¶ New in version 4.0: Available on Windows and macOS as an alternative to
--sslPEMKeyFile
.Specifies a certificate property to select a matching certificate from the operating system’s secure certificate store to use for TLS/SSL.
--sslPEMKeyFile
and--sslCertificateSelector
options are mutually exclusive. You can only specify one.--sslCertificateSelector
accepts an argument of the format<property>=<value>
where the property can be one of the following:Property Value type Description subject
ASCII string Subject name or common name on certificate thumbprint
hex string A sequence of bytes, expressed as hexadecimal, used to identify a public key by its SHA-1 digest.
The
thumbprint
is sometimes referred to as afingerprint
.When using the system SSL certificate store, OCSP (Online Certificate Status Protocol) is used to validate the revocation status of certificates.
The
mongod
searches the operating system’s secure certificate store for the CA certificates required to validate the full certificate chain of the specified TLS/SSL certificate. Specifically, the secure certificate store must contain the root CA and any intermediate CA certificates required to build the full certificate chain to the TLS/SSL certificate. Do not use--sslCAFile
or--sslClusterCAFile
to specify the root and intermediate CA certificateFor example, if the TLS/SSL certificate was signed with a single root CA certificate, the secure certificate store must contain that root CA certificate. If the TLS/SSL certificate was signed with an intermediate CA certificate, the secure certificate store must contain the intermedia CA certificate and the root CA certificate.
-
--sslClusterCertificateSelector
<parameter>=<value>
¶ New in version 4.0: Available on Windows and macOS as an alternative to
--sslClusterFile
.Specifies a certificate property to select a matching certificate from the operating system’s secure certificate store to use for internal x.509 membership authentication.
--sslClusterFile
and--sslClusterCertificateSelector
options are mutually exclusive. You can only specify one.--sslClusterCertificateSelector
accepts an argument of the format<property>=<value>
where the property can be one of the following:Property Value type Description subject
ASCII string Subject name or common name on certificate thumbprint
hex string A sequence of bytes, expressed as hexadecimal, used to identify a public key by its SHA-1 digest.
The
thumbprint
is sometimes referred to as afingerprint
.The
mongod
searches the operating system’s secure certificate store for the CA certificates required to validate the full certificate chain of the specified cluster certificate. Specifically, the secure certificate store must contain the root CA and any intermediate CA certificates required to build the full certificate chain to the cluster certificate. Do not use--sslCAFile
or--sslClusterCAFile
to specify the root and intermediate CA certificate.For example, if the cluster certificate was signed with a single root CA certificate, the secure certificate store must contain that root CA certificate. If the cluster certificate was signed with an intermediate CA certificate, the secure certificate store must contain the intermedia CA certificate and the root CA certificate.
-
--sslClusterPassword
<value>
¶ New in version 2.6.
Specifies the password to de-crypt the x.509 certificate-key file specified with
--sslClusterFile
. Use the--sslClusterPassword
option only if the certificate-key file is encrypted. In all cases, the mongod will redact the password from all logging and reporting output.Starting in MongoDB 4.0:
- On Linux/BSD, if the private key in the x.509 file is encrypted and
you do not specify the
--sslClusterPassword
option, MongoDB will prompt for a passphrase. See TLS/SSL Certificate Passphrase. - On macOS, if the private key in the x.509 file is encrypted, you
must explicitly specify the
--sslClusterPassword
option. Alternatively, you can either use a certificate from the secure system store (see--sslClusterCertificateSelector
) instead of a cluster PEM file or use an unencrypted PEM file. - On Windows, MongoDB does not support encrypted certificates.
The
mongod
fails if it encounters an encrypted PEM file. Use--sslClusterCertificateSelector
instead.
For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
- On Linux/BSD, if the private key in the x.509 file is encrypted and
you do not specify the
-
--sslCAFile
<filename>
¶ Specifies the
.pem
file that contains the root certificate chain from the Certificate Authority. Specify the file name of the.pem
file using relative or absolute paths.- Windows/macOS Only
- If using
--sslCertificateSelector
and/or--sslClusterCertificateSelector
, do not use--sslCAFile
to specify the root and intermediate CA certificates. Store all CA certificates required to validate the full trust chain of the--sslCertificateSelector
and/or--sslClusterCertificateSelector
certificates in the secure certificate store.
For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslClusterCAFile
<filename>
¶ New in version 4.0.3: Specifies the
.pem
file that contains the root certificate chain from the Certificate Authority used to validate the certificate presented by a client establishing a connection. Specify the file name of the.pem
file using relative or absolute paths.--sslClusterCAFile
requires that--sslCAFile
is set.If
--sslClusterCAFile
does not specify the.pem
file for validating the certificate from a client establishing a connection, the cluster uses the.pem
file specified in the--sslCAFile
option.--sslClusterCAFile
lets you use separate Certificate Authorities to verify the client to server and server to client portions of the TLS/SSL handshake.- Windows/macOS Only
- If using
--sslCertificateSelector
and/or--sslClusterCertificateSelector
, do not use--sslClusterCAFile
to specify the root and intermediate CA certificates. Store all CA certificates required to validate the full trust chain of the--sslCertificateSelector
and/or--sslClusterCertificateSelector
certificates in the secure certificate store.
For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslCRLFile
<filename>
¶ Specifies the
.pem
file that contains the Certificate Revocation List. Specify the file name of the.pem
file using relative or absolute paths.Note
Starting in MongoDB 4.0, you cannot specify
--sslCRLFile
on macOS. Use--sslCertificateSelector
instead.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslAllowInvalidCertificates
¶
Bypasses the validation checks for TLS/SSL certificates on other servers in the cluster and allows the use of invalid certificates to connect.
Note
Starting in MongoDB 4.0, if you specify
--sslAllowInvalidCertificates
orssl.allowInvalidCertificates: true
when using x.509 authentication, an invalid certificate is only sufficient to establish a TLS/SSL connection but is insufficient for authentication.When using the
--sslAllowInvalidCertificates
setting, MongoDB logs a warning regarding the use of the invalid certificate.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslAllowInvalidHostnames
¶
New in version 3.0.
Disables the validation of the hostnames in TLS/SSL certificates, when connecting to other members of the replica set or sharded cluster for inter-process authentication. This allows mongod to connect to other members if the hostnames in their certificates do not match their configured hostname.
For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslAllowConnectionsWithoutCertificates
¶
For clients that do not present certificates, mongod bypasses TLS/SSL certificate validation when establishing the connection.
For clients that present a certificate, however, mongod performs certificate validation using the root certificate chain specified by
--sslCAFile
and reject clients with invalid certificates.Use the
--sslAllowConnectionsWithoutCertificates
option if you have a mixed deployment that includes clients that do not or cannot present certificates to the mongod.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslDisabledProtocols
<protocol(s)>
¶ New in version 3.0.7.
Prevents a MongoDB server running with TLS/SSL from accepting incoming connections that use a specific protocol or protocols. To specify multiple protocols, use a comma separated list of protocols.
--sslDisabledProtocols
recognizes the following protocols:TLS1_0
,TLS1_1
,TLS1_2
, and starting in version 4.0.4 (and 3.6.9 and 3.4.24),TLS1_3
.- On macOS, you cannot disable
TLS1_1
and leave bothTLS1_0
andTLS1_2
enabled. You must disable at least one of the other two, for example,TLS1_0,TLS1_1
. - To list multiple protocols, specify as a comma separated list of
protocols. For example
TLS1_0,TLS1_1
. - Specifying an unrecognized protocol will prevent the server from starting.
- The specified disabled protocols overrides any default disabled protocols.
Starting in version 4.0, MongoDB disables the use of TLS 1.0 if TLS 1.1+ is available on the system. To enable the disabled TLS 1.0, specify
none
to--sslDisabledProtocols
. See Disable TLS 1.0.Members of replica sets and sharded clusters must speak at least one protocol in common.
See also
- On macOS, you cannot disable
-
--sslFIPSMode
¶
Directs the mongod to use the FIPS mode of the TLS/SSL library. Your system must have a FIPS compliant library to use the
--sslFIPSMode
option.Note
FIPS-compatible TLS/SSL is available only in MongoDB Enterprise. See Configure MongoDB for FIPS for more information.
Profiler Options¶
-
--profile
<level>
¶ Default: 0
Configures the database profiler level. The following profiler levels are available:
Level Description 0
The profiler is off and does not collect any data. This is the default profiler level. 1
The profiler collects data for operations that take longer than the value of slowms
.2
The profiler collects data for all operations. Important
Profiling can impact performance and shares settings with the system log. Carefully consider any performance and security implications before configuring and enabling the profiler on a production deployment.
See Profiler Overhead for more information on potential performance degradation.
-
--slowms
<integer>
¶ Default: 100
The slow operation time threshold, in milliseconds. Operations that run for longer than this threshold are considered slow.
When
logLevel
is set to0
, MongoDB records slow operations to the diagnostic log at a rate determined byslowOpSampleRate
. Starting in MongoDB 4.0.6, the secondaries of replica sets log all oplog entry messages that take longer than the slow operation threshold to apply regardless of the sample rate.At higher
logLevel
settings, all operations appear in the diagnostic log regardless of their latency with the following exception: the logging of slow oplog entry messages by the secondaries. The secondaries log only the slow oplog entries; increasing thelogLevel
does not log all oplog entries.For
mongod
instances,--slowms
affects the diagnostic log and, if enabled, the profiler.See also
-
--slowOpSampleRate
<double>
¶ Default: 1.0
The fraction of slow operations that should be profiled or logged.
--slowOpSampleRate
accepts values between 0 and 1, inclusive.--slowOpSampleRate
does not affect the slow oplog entry logging by the secondary members of a replica set. Secondary members log all oplog entries that take longer than the slow operation threshold regardless of the--slowOpSampleRate
.For
mongod
instances,--slowOpSampleRate
affects the diagnostic log and, if enabled, the profiler.
Audit Options¶
-
--auditDestination
¶
Enables auditing and specifies where mongod sends all audit events.
--auditDestination
can have one of the following values:Value Description syslog
Output the audit events to syslog in JSON format. Not available on Windows. Audit messages have a syslog severity level of
info
and a facility level ofuser
.The syslog message limit can result in the truncation of audit messages. The auditing system will neither detect the truncation nor error upon its occurrence.
console
Output the audit events to stdout
in JSON format.file
Output the audit events to the file specified in --auditPath
in the format specified in--auditFormat
.Note
Available only in MongoDB Enterprise and MongoDB Atlas.
-
--auditFormat
¶
New in version 2.6.
Specifies the format of the output file for auditing if
--auditDestination
isfile
. The--auditFormat
option can have one of the following values:Value Description JSON
Output the audit events in JSON format to the file specified in --auditPath
.BSON
Output the audit events in BSON binary format to the file specified in --auditPath
.Printing audit events to a file in JSON format degrades server performance more than printing to a file in BSON format.
Note
Available only in MongoDB Enterprise and MongoDB Atlas.
-
--auditPath
¶
New in version 2.6.
Specifies the output file for auditing if
--auditDestination
has value offile
. The--auditPath
option can take either a full path name or a relative path name.Note
Available only in MongoDB Enterprise and MongoDB Atlas.
-
--auditFilter
¶
New in version 2.6.
Specifies the filter to limit the types of operations the audit system records. The option takes a string representation of a query document of the form:
The
<field>
can be any field in the audit message, including fields returned in the param document. The<expression>
is a query condition expression.To specify an audit filter, enclose the filter document in single quotes to pass the document as a string.
To specify the audit filter in a configuration file, you must use the YAML format of the configuration file.
Note
Available only in MongoDB Enterprise and MongoDB Atlas.
SNMP Options¶
Note
MongoDB Enterprise on macOS does not include support for SNMP due to SERVER-29352.
-
--snmp-disabled
¶
Disables SNMP access to
mongod
. The option is incompatible with--snmp-subagent
and--snmp-master
.New in version 4.0.6.
-
--snmp-subagent
¶
Runs SNMP as a subagent. The option is incompatible with
--snmp-disabled
.
-
--snmp-master
¶
Runs SNMP as a master. The option is incompatible with
--snmp-disabled
.
inMemory Options¶
-
--inMemorySizeGB
<float>
¶ Default: 50% of physical RAM less 1 GB
Changed in version 3.4: Values can range from 256MB to 10TB and can be a float.
Maximum amount of memory to allocate for in-memory storage engine data, including indexes, oplog if the
mongod
is part of replica set, replica set or sharded cluster metadata, etc.By default, the in-memory storage engine uses 50% of physical RAM minus 1 GB.
Enterprise Feature
Available in MongoDB Enterprise only.
Encryption Key Management Options¶
-
--enableEncryption
¶
Default: false
New in version 3.2.
Enables encryption for the WiredTiger storage engine. This option must be enabled in order to pass in encryption keys and configurations.
Enterprise Feature
Available in MongoDB Enterprise only.
-
--encryptionCipherMode
<string>
¶ Default: AES256-CBC
New in version 3.2.
The cipher mode to use for encryption at rest:
Mode Description AES256-CBC
256-bit Advanced Encryption Standard in Cipher Block Chaining Mode AES256-GCM
256-bit Advanced Encryption Standard in Galois/Counter Mode
Changed in version 4.0: MongoDB Enterprise on Windows no longer supports
AES256-GCM
. This cipher is now available only on Linux.Enterprise Feature
Available in MongoDB Enterprise only.
-
--encryptionKeyFile
<string>
¶ New in version 3.2.
The path to the local keyfile when managing keys via process other than KMIP. Only set when managing keys via process other than KMIP. If data is already encrypted using KMIP, MongoDB will throw an error.
Requires
--enableEncryption
.Enterprise Feature
Available in MongoDB Enterprise only.
-
--kmipKeyIdentifier
<string>
¶ New in version 3.2.
Unique KMIP identifier for an existing key within the KMIP server. Include to use the key associated with the identifier as the system key. You can only use the setting the first time you enable encryption for the
mongod
instance. Requires--enableEncryption
.If unspecified, MongoDB will request that the KMIP server create a new key to utilize as the system key.
If the KMIP server cannot locate a key with the specified identifier or the data is already encrypted with a key, MongoDB will throw an error
Enterprise Feature
Available in MongoDB Enterprise only.
-
--kmipRotateMasterKey
<boolean>
¶ Default: false
New in version 3.2.
If true, rotate the master key and re-encrypt the internal keystore.
Enterprise Feature
Available in MongoDB Enterprise only.
See also
-
--kmipServerName
<string>
¶ New in version 3.2.
Hostname or IP address of the KMIP server to connect to. Requires
--enableEncryption
.Starting in MongoDB 4.0.14, you can specify multiple KMIP servers as a comma-separated list, e.g.
server1.example.com,server2.example.com
. On startup, themongod
will attempt to establish a connection to each server in the order listed, and will select the first server to which it can successfully establish a connection. KMIP server selection occurs only at startup.When connecting to a KMIP server, the
mongod
verifies that the specified--kmipServerName
matches the Subject Alternative NameSAN
(or, ifSAN
is not present, the Common NameCN
) in the certificate presented by the KMIP server. IfSAN
is present,mongod
does not match against theCN
. If the hostname does not match theSAN
(orCN
), themongod
will fail to connect.Enterprise Feature
Available in MongoDB Enterprise only.
-
--kmipPort
<number>
¶ Default: 5696
New in version 3.2.
Port number to use to communicate with the KMIP server. Requires
--kmipServerName
. Requires--enableEncryption
.If specifying multiple KMIP servers with
--kmipServerName
, themongod
will use the port specified with--kmipPort
for all provided KMIP servers.Enterprise Feature
Available in MongoDB Enterprise only.
-
--kmipClientCertificateSelector
<string>
¶ New in version 4.0: Available on Windows and macOS as an alternative to
--kmipClientCertificateFile
.--kmipClientCertificateFile
and--kmipClientCertificateSelector
options are mutually exclusive. You can only specify one.Specifies a certificate property in order to select a matching certificate from the operating system’s certificate store to authenticate MongoDB to the KMIP server.
--kmipClientCertificateSelector
accepts an argument of the format<property>=<value>
where the property can be one of the following:Property Value type Description subject
ASCII string Subject name or common name on certificate thumbprint
hex string A sequence of bytes, expressed as hexadecimal, used to identify a public key by its SHA-1 digest.
The
thumbprint
is sometimes referred to as afingerprint
.Enterprise Feature
Available in MongoDB Enterprise only.
-
--kmipClientCertificateFile
<string>
¶ New in version 3.2.
String containing the path to the client certificate used for authenticating MongoDB to the KMIP server. Requires that a
kmipServerName
be provided.Note
Starting in 4.0, on macOS or Windows, you can use a certificate from the operating system’s secure store instead of a PEM key file. See
--kmipClientCertificateSelector
.Enterprise Feature
Available in MongoDB Enterprise only.
-
--kmipClientCertificatePassword
<string>
¶ New in version 3.2.
The password (if one exists) for the client certificate passed into
kmipClientCertificateFile
. Is used for authenticating MongoDB to the KMIP server. Requires that akmipClientCertificateFile
be provided.Enterprise Feature
Available in MongoDB Enterprise only.
-
--kmipServerCAFile
<string>
¶ New in version 3.2.
Path to CA File. Used for validating secure client connection to KMIP server.
Note
Starting in 4.0, on macOS or Windows, you can use a certificate from the operating system’s secure store instead of a PEM key file. See
--kmipClientCertificateSelector
. When using the secure store, you do not need to, but can, also specify the--kmipServerCAFile
.