serverStatus

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Definition

Syntax
Behavior
Output
Output Changelog

This version of the documentation is archived and no longer supported. View the current documentation to learn how to upgrade your version of MongoDB.

Definition

serverStatus: The serverStatus command returns a document that provides an overview of the database's state. Monitoring applications can run this command at a regular interval to collect statistics about the instance.

Syntax

The command has the following syntax:

db.runCommand( { serverStatus: 1 } )

The value (i.e. 1 above) does not affect the operation of the command. The db.serverStatus() command returns a large amount of data. To return a specific object or field from the output append the object or field name to the command.

For example:

db.runCommand({ serverStatus: 1}).metrics
db.runCommand({ serverStatus: 1}).metrics.commands
db.runCommand({ serverStatus: 1}).metrics.commands.update

The mongo shell provides the db.serverStatus() wrapper for the serverStatus command.

Tip

Behavior

By default, serverStatus excludes in its output:

some content in the repl document.
mirroredReads document. (Available starting in version 4.4)

To include fields that are excluded by default, specify the top-level field and set it to 1 in the command. To exclude fields that are included by default, specify the top-level field and set to 0 in the command.

For example, the following operation suppresses the repl, metrics and locks information in the output.

db.runCommand( { serverStatus: 1, repl: 0, metrics: 0, locks: 0 } )

The following example includes all repl information in the output:

db.runCommand( { serverStatus: 1,  repl: 1 } )

Initialization

The statistics reported by serverStatus are reset when the mongod server is restarted.

This command will always return a value, even on a fresh database. The related command db.serverStatus() does not always return a value unless a counter has started to increment for a particular metric.

After you run an update query, db.serverStatus() and db.runCommand({ serverStatus: 1}) both return the same values.

{
   "arrayFilters" : NumberLong(0),
   "failed" : NumberLong(0),
   "pipeline" : NumberLong(0),
   "total" : NumberLong(1)
}

Include `mirroredReads`

By default, the mirroredReads information (available starting in version 4.4) is not included in the output. To return mirroredReads information, you must explicitly specify the inclusion:

db.runCommand( { serverStatus: 1, mirroredReads: 1 } )

Include `latchAnalysis`

By default, the latchAnalysis information (available starting in version 4.4) is not included in the output. To return latchAnalysis information, you must explicitly specify the inclusion:

db.runCommand( { serverStatus: 1, latchAnalysis: 1 } )

Change `tcmalloc` Verbosity

By default, tcmalloc information is included in the output. This section provides memory allocation statistics for your database. To change the verbosity of the tcmalloc section, specify an integer between 0 and 2 (inclusive):

db.runCommand( { serverStatus: 1, tcmalloc: <int> } )

The command has the following behavior:

By default, tcmalloc is set to 1.
Passing a larger integer value increases the verbosity.
Passing 0 or false omits the tcmalloc section from the output.
Passing any other input results in the default setting.

For more information about how MongoDB allocates memory, see TCMalloc.

Output

Note

The output fields vary depending on the version of MongoDB, underlying operating system platform, the storage engine, and the kind of node, including mongos, mongod or replica set member.

For the serverStatus output specific to the version of your MongoDB, refer to the appropriate version of the MongoDB Manual.

Instance Information

"host" : <string>,
"advisoryHostFQDNs" : <array>,
"version" : <string>,
"process" : <"mongod"|"mongos">,
"pid" : <num>,
"uptime" : <num>,
"uptimeMillis" : <num>,
"uptimeEstimate" : <num>,
"localTime" : ISODate(""),

host: The system's hostname. In Unix/Linux systems, this should be the same as the output of the hostname command.

advisoryHostFQDNs: New in version 3.2.
An array of the system's fully qualified domain names (FQDNs).

version: The MongoDB version of the current MongoDB process.

process: The current MongoDB process. Possible values are: mongos or mongod.

pid: The process id number.

uptime: The number of seconds that the current MongoDB process has been active.

uptimeMillis: The number of milliseconds that the current MongoDB process has been active.

uptimeEstimate: The uptime in seconds as calculated from MongoDB's internal course-grained time keeping system.

localTime: The ISODate representing the current time, according to the server, in UTC.

asserts

"asserts" : {
   "regular" : <num>,
   "warning" : <num>,
   "msg" : <num>,
   "user" : <num>,
   "rollovers" : <num>
},

asserts: A document that reports on the number of assertions raised since the MongoDB process started. While assert errors are typically uncommon, if there are non-zero values for the asserts, you should check the log file for more information. In many cases, these errors are trivial, but are worth investigating.

asserts.regular: The number of regular assertions raised since the MongoDB process started. Check the log file for more information about these messages.

asserts.warning: This field always returns zero 0.

asserts.msg: The number of message assertions raised since the MongoDB process started. Check the log file for more information about these messages.

asserts.user: The number of "user asserts" that have occurred since the last time the MongoDB process started. These are errors that user may generate, such as out of disk space or duplicate key. You can prevent these assertions by fixing a problem with your application or deployment. Check the MongoDB log for more information.

asserts.rollovers: The number of times that the assert counters have rolled over since the last time the MongoDB process started. The counters will roll over to zero after 2 ³⁰ assertions. Use this value to provide context to the other values in the asserts data structure.

connections

"connections" : {
   "current" : <num>,
   "available" : <num>,
   "totalCreated" : <num>,
   "active" : <num>,
   "exhaustIsMaster" : <num>,
   "exhaustHello" : <num>,
   "awaitingTopologyChanges" : <num>
},

connections: A document that reports on the status of the connections. Use these values to assess the current load and capacity requirements of the server.

connections.current

The number of incoming connections from clients to the database server . This number includes the current shell session. Consider the value of connections.available to add more context to this datum.

The value will include all incoming connections including any shell connections or connections from other servers, such as replica set members or mongos instances.

connections.available: The number of unused incoming connections available. Consider this value in combination with the value of connections.current to understand the connection load on the database, and the UNIX ulimit Settings document for more information about system thresholds on available connections.

connections.totalCreated: Count of all incoming connections created to the server. This number includes connections that have since closed.

connections.active: The number of active client connections to the server. Active client connections refers to client connections that currently have operations in progress.

connections.exhaustIsMaster: The number of connections whose last request was an isMaster request with exhaustAllowed.
New in version 4.4.

connections.exhaustHello: The number of connections whose last request was a hello request with exhaustAllowed.
New in version 4.4.2.

connections.awaitingTopologyChanges: The number of clients currently waiting in a hello or an isMaster request for a topology change.
New in version 4.4.

defaultRWConcern

Available starting in 4.4

The defaultRWConcern section provides information on the local copy of the global default read or write concern settings. The data may be stale or out of date. See getDefaultRWConcern for more information.

"defaultRWConcern" : {
  "defaultReadConcern" : {
    "level" : <string>
  },
  "defaultWriteConcern" : {
    "w" : <string> | <int>,
    "wtimeout" : <int>,
    "j" : <bool>
  },
  "updateOpTime" : Timestamp,
  "updateWallClockTime" : Date,
  "localUpdateWallClockTime" : Date
}

defaultRWConcern: The last known global default read or write concern settings.
New in version 4.4.

defaultRWConcern.defaultReadConcern

The last known global default read concern setting.

If serverStatus does not return this field, the global default read concern has either not been set or has not yet propagated to the instance.

New in version 4.4.

defaultRWConcern.defaultReadConcern.level

The last known global default read concern level setting.

If serverStatus does not return this field, the global default for this setting has either not been set or has not yet propagated to the instance.

New in version 4.4.

defaultRWConcern.defaultWriteConcern

The last known global default write concern setting.

If serverStatus does not return this field, the global default write concern has either not been set or has not yet propagated to the instance.

New in version 4.4.

defaultRWConcern.defaultWriteConcern.w

The last known global default w setting.

If serverStatus does not return this field, the global default for this setting has either not been set or has not yet propagated to the instance.

New in version 4.4.

defaultRWConcern.defaultWriteConcern.wtimeout

The last known global default wtimeout setting.

If serverStatus does not return this field, the global default for this setting has either not been set or has not yet propagated to the instance.

New in version 4.4.

defaultRWConcern.updateOpTime: The timestamp when the instance last updated its copy of any global read or write concern settings. If the defaultRWConcern.defaultReadConcern and defaultRWConcern.defaultWriteConcern fields are absent, this field indicates the timestamp when the defaults were last unset.
New in version 4.4.

defaultRWConcern.updateWallClockTime: The wall clock time when the instance last updated its copy of any global read or write concern settings. If the defaultRWConcern.defaultReadConcern and defaultRWConcern.defaultWriteConcern fields are absent, this field indicates the time when the defaults were last unset.
New in version 4.4.

defaultRWConcern.localUpdateWallClockTime: The local system wall clock time when the instance last updated its copy of any global read or write concern setting. If this field is the only field under defaultRWConcern, the instance has never had knowledge of a global default read or write concern setting.
New in version 4.4.

electionMetrics

New in version 4.2.1.

The electionMetrics section provides information on elections called by this mongod instance in a bid to become the primary:

"electionMetrics" : {
   "stepUpCmd" : {
      "called" : <NumberLong>,
      "successful" : <NumberLong>
   },
   "priorityTakeover" : {
      "called" : <NumberLong>,
      "successful" : <NumberLong>
   },
   "catchUpTakeover" : {
      "called" : <NumberLong>,
      "successful" : <NumberLong>
   },
   "electionTimeout" : {
      "called" : <NumberLong>,
      "successful" : <NumberLong>
   },
   "freezeTimeout" : {
      "called" : <NumberLong>,
      "successful" : <NumberLong>
   },
   "numStepDownsCausedByHigherTerm" : <NumberLong>,
   "numCatchUps" : <NumberLong>,
   "numCatchUpsSucceeded" : <NumberLong>,
   "numCatchUpsAlreadyCaughtUp" : <NumberLong>,
   "numCatchUpsSkipped" : <NumberLong>,
   "numCatchUpsTimedOut" : <NumberLong>,
   "numCatchUpsFailedWithError" :<NumberLong>,
   "numCatchUpsFailedWithNewTerm" : <NumberLong>,
   "numCatchUpsFailedWithReplSetAbortPrimaryCatchUpCmd" : <NumberLong>,
   "averageCatchUpOps" : <double>
}

electionMetrics.stepUpCmd

Metrics on elections that were called by the mongod instance as part of an election handoff when the primary stepped down.

The stepUpCmd includes both the number of elections called and the number of elections that succeeded.

New in version 4.2.1.

electionMetrics.priorityTakeover

Metrics on elections that were called by the mongod instance because its priority is higher than the primary's.

The electionMetrics.priorityTakeover includes both the number of elections called and the number of elections that succeeded.

New in version 4.2.1.

electionMetrics.catchUpTakeover

Metrics on elections called by the mongod instance because it is more-up-to-date than the primary.

The catchUpTakeover includes both the number of elections called and the number of elections that succeeded.

Tip

extra_info

"extra_info" : {
   "note" : "fields vary by platform.",
   "page_faults" : <num>
},

extra_info: A document that provides additional information regarding the underlying system.

extra_info.note: A string with the text "fields vary by platform."

extra_info.page_faults

The total number of page faults. The extra_info.page_faults counter may increase dramatically during moments of poor performance and may correlate with limited memory environments and larger data sets. Limited and sporadic page faults do not necessarily indicate an issue.

Windows draws a distinction between "hard" page faults involving disk I/O, and "soft" page faults that only require moving pages in memory. MongoDB counts both hard and soft page faults in this statistic.

flowControl

New in version 4.2.

"flowControl" : {
   "enabled" : <boolean>,
   "targetRateLimit" : <int>,
   "timeAcquiringMicros" : <NumberLong>,
   "locksPerKiloOp" : <double>,  // Available in 4.4+. In 4.2, returned locksPerOp instead.
   "sustainerRate" : <int>,
   "isLagged" : <boolean>,
   "isLaggedCount" : <int>,
   "isLaggedTimeMicros" : <NumberLong>,
},

flowControl: A document that returns statistics on the Flow Control. With flow control enabled, as the majority commit point lag grows close to the flowControlTargetLagSeconds, writes on the primary must obtain tickets before taking locks. As such, the metrics returned are meaningful when run on the primary.
New in version 4.2.

flowControl.enabled

A boolean that indicates whether Flow Control is enabled(true) or disabled (false).

Note

Starting in MongoDB 4.4

locksPerKiloOp replaces locksPerOp field. locksPerOp field is available only on version 4.2.

When run on the primary, an approximation of the number of locks taken per 1000 operations.

When run on a secondary, the returned number is a placeholder.

New in version 4.4.

flowControl.locksPerOp

Note

Available on MongoDB 4.2 only

MongoDB 4.4 replaces locksPerOp with flowControl.locksPerKiloOp.

When run on the primary, an approximation of the number of locks taken per operation.

When run on a secondary, the returned number is a placeholder.

New in version 4.2.

flowControl.sustainerRate

When run on the primary, an approximation of operations applied per second by the secondary that is sustaining the commit point.

When run on a secondary, the returned number is a placeholder.

New in version 4.2.

flowControl.isLagged

When run on the primary, a boolean that indicates whether flow control has engaged. Flow control engages when the majority committed lag is greater than some percentage of the configured flowControlTargetLagSeconds.

When run on a secondary, the returned boolean is a placeholder.

New in version 4.2.

flowControl.isLaggedCount

When run on a primary, the number of times flow control has engaged since the last restart. Flow control engages when the majority committed lag is greater than some percentage of the flowControlTargetLagSeconds.

When run on a secondary, the returned number is a placeholder.

New in version 4.2.

flowControl.isLaggedTimeMicros

When run on the primary, the amount of time flow control has spent being engaged since the last restart. Flow control engages when the majority committed lag is greater than some percentage of the flowControlTargetLagSeconds.

When run on a secondary, the returned number is a placeholder.

New in version 4.2.

globalLock

"globalLock" : {
   "totalTime" : <num>,
   "currentQueue" : {
      "total" : <num>,
      "readers" : <num>,
      "writers" : <num>
   },
   "activeClients" : {
      "total" : <num>,
      "readers" : <num>,
      "writers" : <num>
   }
},

globalLock

A document that reports on the database's lock state.

Generally, the locks document provides more detailed data on lock uses.

globalLock.totalTime: The time, in microseconds, since the database last started and created the globalLock. This is roughly equivalent to total server uptime.

globalLock.currentQueue: A document that provides information concerning the number of operations queued because of a lock.

globalLock.currentQueue.total

The total number of operations queued waiting for the lock (i.e., the sum of globalLock.currentQueue.readers and globalLock.currentQueue.writers).

A consistently small queue, particularly of shorter operations, should cause no concern. The globalLock.activeClients readers and writers information provides context for this data.

globalLock.currentQueue.readers: The number of operations that are currently queued and waiting for the read lock. A consistently small read-queue, particularly of shorter operations, should cause no concern.

globalLock.currentQueue.writers: The number of operations that are currently queued and waiting for the write lock. A consistently small write-queue, particularly of shorter operations, is no cause for concern.

globalLock.activeClients

A document that provides information about the number of connected clients and the read and write operations performed by these clients.

Use this data to provide context for the globalLock.currentQueue data.

globalLock.activeClients.total: The total number of internal client connections to the database including system threads as well as queued readers and writers. This metric will be higher than the total of activeClients.readers and activeClients.writers due to the inclusion of system threads.

globalLock.activeClients.readers: The number of the active client connections performing read operations.

globalLock.activeClients.writers: The number of active client connections performing write operations.

hedgingMetrics

New in version 4.4: For mongos instances only.

"hedgingMetrics" : {
   "numTotalOperations" : <num>,
   "numTotalHedgedOperations" : <num>,
   "numAdvantageouslyHedgedOperations" : <num>
},

hedgingMetrics: Provides metrics on hedged reads for the mongos instance.
New in version 4.4: For mongos instances only.

hedgingMetrics.numTotalOperations: The total number of the operations issued with the hedged read option enabled to this mongos instance.
New in version 4.4: For mongos instances only.

hedgingMetrics.numTotalHedgedOperations: The number of all operations for which the mongos instance hedged the read operation; i.e. sent the operation to an additional member of each queried shard.
New in version 4.4: For mongos instances only.

hedgingMetrics.numAdvantageouslyHedgedOperations: The total number of the operation where the additional read sent to hedge the read operation fulfilled the client request.
New in version 4.4: For mongos instances only.

indexBulkBuilder

"indexBulkBuilder": {
   "count": <long>,
   "resumed": <long>,
   "filesOpenedForExternalSort": <long>,
   "filesClosedForExternalSort": <long>,
}

indexBulkBuilder: Provides metrics for index bulk builder operations. Use these metrics to diagnose index build issues with createIndexes, collection cloning during initial sync, index builds that resume after startup, and statistics on disk usage by the external sorter.

indexBulkBuilder.count: The number of instances of the bulk builder created.

indexBulkBuilder.filesClosedForExternalSort: The number of times the external sorter closed a file handle to spill data to disk. Combine this value with filesOpenedForExternalSort to determine the number of open file handles in use by the external sorter.

indexBulkBuilder.filesOpenedForExternalSort: The number of times the external sorter opened a file handle to spill data to disk. Combine this value with filesClosedForExternalSort to determine the number of open file handles in use by the external sorter.

indexBulkBuilder.resumed: The number of times the bulk builder was created for a resumable index build.

latchAnalysis

New in version 4.4.

"latchAnalysis" : {
   <latch name> : {
      "created" : <num>,
      "destroyed" : <num>,
      "acquired" : <num>,
      "released" : <num>,
      "contended" : <num>,
      "hierarchicalAcquisitionLevelViolations" : {
            "onAcquire" : <num>,
            "onRelease" : <num>
      }
   },
   ...

latchAnalysis

A document that reports on metrics related to internal locking primitives (a.k.a. latches).

To return latchAnalysis information, you must explicitly specify the inclusion:

db.runCommand( { serverStatus: 1, latchAnalysis: 1 } )

The latchAnalysis returns for each latch the <latch name> and the following associated metrics:

Metric	Description
`created`	Number of times the latch was created.
`destroyed`	Number of times the latch was destroyed.
`acquired`	Number of times the latch was acquired.
`released`	Number of times the latch was released.
`contended`	Number of times the latch had contention.
`hierarchicalAcquisitionLevelViolations`	Only returned if violations exist Contains the following fields: `onAcquire` Number of times the latch hierarchy (i.e. the latch level ordering) has been violated during latch acquisition. `onRelease` Number of times the latch hierarchy (i.e. the latch level ordering) has been violated during latch release.

New in version 4.4.

logicalSessionRecordCache

New in version 3.6.

"logicalSessionRecordCache" : {
   "activeSessionsCount" : <num>,
   "sessionsCollectionJobCount" : <num>,
   "lastSessionsCollectionJobDurationMillis" : <num>,
   "lastSessionsCollectionJobTimestamp" : <Date>,
   "lastSessionsCollectionJobEntriesRefreshed" : <num>,
   "lastSessionsCollectionJobEntriesEnded" : <num>,
   "lastSessionsCollectionJobCursorsClosed" : <num>,
   "transactionReaperJobCount" : <num>,
   "lastTransactionReaperJobDurationMillis" : <num>,
   "lastTransactionReaperJobTimestamp" : <Date>,
   "lastTransactionReaperJobEntriesCleanedUp" : <num>,
   "sessionCatalogSize" : <num>   // Starting in MongoDB 4.2
},

logicalSessionRecordCache: Provides metrics around the caching of server sessions.

logicalSessionRecordCache.activeSessionsCount

The number of all active local sessions cached in memory by the mongod or mongos instance since the last refresh period.

Tip

locks

"locks" : {
   <type> : {
         "acquireCount" : {
            <mode> : NumberLong(<num>),
            ...
         },
         "acquireWaitCount" : {
            <mode> : NumberLong(<num>),
            ...
         },
         "timeAcquiringMicros" : {
            <mode> : NumberLong(<num>),
            ...
         },
         "deadlockCount" : {
            <mode> : NumberLong(<num>),
            ...
         }
   },
   ...

locks

A document that reports for each lock <type>, data on lock <modes>.

The possible lock <types> are:

Lock Type	Description
`ParallelBatchWriterMode`	Represents a lock for parallel batch writer mode. In earlier versions, PBWM information was reported as part of the `Global` lock information. New in version 4.2.
`ReplicationStateTransition`	Represents lock taken for replica set member state transitions. New in version 4.2.
`Global`	Represents global lock.
`Database`	Represents database lock.
`Collection`	Represents collection lock.
`Mutex`	Represents mutex.
`Metadata`	Represents metadata lock.
`oplog`	Represents lock on the oplog.

The possible <modes> are:

Lock Mode	Description
`R`	Represents Shared (S) lock.
`W`	Represents Exclusive (X) lock.
`r`	Represents Intent Shared (IS) lock.
`w`	Represents Intent Exclusive (IX) lock.

All values are of the NumberLong() type.

locks.<type>.acquireCount: Number of times the lock was acquired in the specified mode.

locks.<type>.acquireWaitCount: Number of times the locks.<type>.acquireCount lock acquisitions encountered waits because the locks were held in a conflicting mode.

locks.<type>.timeAcquiringMicros

Cumulative wait time in microseconds for the lock acquisitions.

locks.<type>.timeAcquiringMicros divided by locks.<type>.acquireWaitCount gives an approximate average wait time for the particular lock mode.

locks.<type>.deadlockCount: Number of times the lock acquisitions encountered deadlocks.

mirroredReads

Available on mongod only.

"mirroredReads" : {
      "seen" : <num>,
      "sent" : <num>
},

mirroredReads

Available on mongod only.

A document that reports on mirrored reads. To return mirroredReads information, you must explicitly specify the inclusion:

db.runCommand( { serverStatus: 1, mirroredReads: 1 } )

mirroredReads.seen: The number of operations that support mirroring received by this member.
Tip
See also:
mirrorReads Parameter
New in version 4.4.

mirroredReads.sent: The number of mirrored reads sent by this member when primary. For example, if a read is mirrored and sent to two secondaries, the number of mirrored reads is 2.
Tip
See also:
mirrorReads Parameter
New in version 4.4.

network

network : {
   bytesIn : Long("<num>"),
   bytesOut : Long("<num>"),
   numSlowDNSOperations : Long("<num>"),
   numSlowSSLOperations : Long("<num>"),
   numRequests : Long("<num>"),
   tcpFastOpen : {
      serverSupported : <bool>,
      clientSupported : <bool>,
      accepted : Long("<num>")
   },
   compression : {
      snappy : {
         compressor : { bytesIn : Long("<num>"), bytesOut : Long("<num>") },
         decompressor : { bytesIn : Long("<num>"), bytesOut : Long("<num>") }
      },
      zstd : {
         compressor : { bytesIn : Long("<num>"), bytesOut : Long("<num>") },
         decompressor : { bytesIn : Long("<num>"), bytesOut : Long("<num>") }
      },
      zlib : {
         compressor : { bytesIn : Long("<num>"), bytesOut : Long("<num>") },
         decompressor : { bytesIn : Long("<num>"), bytesOut : Long("<num>") }
      }
   }
}

network: A document that reports data on MongoDB's network use. These statistics measure ingress connections only, i.e. traffic seen by the mongod / mongos over network connections initiated by clients or other mongod / mongos instances. Traffic from network connections initiated by this mongod / mongos instance (i.e. egress connections) is not measured in these statistics.

network.bytesIn: The total number of bytes that the server has received over network connections initiated by clients or other mongod / mongos instances.

network.bytesOut: The total number of bytes that the server has sent over network connections initiated by clients or other mongod / mongos instances.

network.numSlowDNSOperations: New in version 4.4.
The total number of DNS resolution operations which took longer than 1 second.

network.numSlowSSLOperations: New in version 4.4.
The total number of SSL handshake operations which took longer than 1 second.

network.numRequests: The total number of distinct requests that the server has received. Use this value to provide context for the network.bytesIn and network.bytesOut values to ensure that MongoDB's network utilization is consistent with expectations and application use.

network.tcpFastOpen: New in version 4.4.
A document that reports data on MongoDB's support and use of TCP Fast Open (TFO) connections.

network.tcpFastOpen.kernelSetting

New in version 4.4.

Linux only

Returns the value of /proc/sys/net/ipv4/tcp_fastopen:

0 - TCP Fast Open is disabled on the system.
1 - TCP Fast Open is enabled for outgoing connections.
2 - TCP Fast Open is enabled for incoming connections.
3 - TCP Fast Open is enabled for incoming and outgoing connections.

network.tcpFastOpen.serverSupported

New in version 4.4.

Returns true if the host operating system supports inbound TCP Fast Open (TFO) connections.
Returns false if the host operating system does not support inbound TCP Fast Open (TFO) connections.

network.tcpFastOpen.clientSupported

New in version 4.4.

Returns true if the host operating system supports outbound TCP Fast Open (TFO) connections.
Returns false if the host operating system does not support outbound TCP Fast Open (TFO) connections.

network.tcpFastOpen.accepted: New in version 4.4.
The total number of accepted incoming TCP Fast Open (TFO) connections to the mongod or mongos since the mongod or mongos last started.

network.compression: A document that reports on the amount of data compressed and decompressed by each network compressor library.

network.compression.snappy: A document that returns statistics on the number of bytes that have been compressed and decompressed with the snappy library.

network.compression.zstd: A document that returns statistics on the number of bytes that have been compressed and decompressed with the zstd library.

network.compression.zlib: A document that returns statistics on the number of bytes that have been compressed and decompressed with the zlib library.

opLatencies

Only for ``mongod`` instances

"opLatencies" : {
   "reads" : <document>,
   "writes" : <document>,
   "commands" : <document>
},

opLatencies

A document containing operation latencies for the instance as a whole. See latencyStats Document for an description of this document.

Only mongod instances report opLatencies.

opLatencies.reads: Latency statistics for read requests.

opLatencies.writes: Latency statistics for write operations.

opLatencies.commands: Latency statistics for database commands.

opReadConcernCounters

New in version 4.0.6.

Only for mongod instances

"opReadConcernCounters" : {
   "available" : NumberLong(<num>),
   "linearizable" : NumberLong(<num>),
   "local" : NumberLong(<num>),
   "majority" : NumberLong(<num>),
   "snapshot" : NumberLong(<num>),
   "none" :  NumberLong(<num>)
}

opReadConcernCounters

New in version 4.0.6.

A document that reports on the read concern level specified by query operations to the mongod instance since it last started.

Specified `w`	Description
`"available"`	Number of query operations that specified read concern level `"available"`.
`"linearizable"`	Number of query operations that specified read concern level `"linearizable"`.
`"local"`	Number of query operations that specified read concern level `"local"`.
`"majority"`	Number of query operations that specified read concern level `"majority"`.
`"snapshot"`	Number of query operations that specified read concern level `"snapshot"`.
`"none"`	Number of query operations that did not specify a read concern level and instead used the default read concern level.

The sum of the opReadConcernCounters equals opcounters.query.

opWriteConcernCounters

Only for mongod instances

"opWriteConcernCounters" : {
   "insert" : {
      "wmajority" : NumberLong(<num>),
      "wnum" : {
         "<num>" :  NumberLong(<num>),
         ...
      },
      "wtag" : {
         "<tag1>" :  NumberLong(<num>),
         ...
      },
      "none" : NumberLong(<num>)
   },
   "update" : {
      "wmajority" : NumberLong(<num>),
      "wnum" : {
         "<num>" :  NumberLong(<num>),
      },
      "wtag" : {
         "<tag1>" :  NumberLong(<num>),
         ...
      },
      "none" : NumberLong(<num>)
   },
   "delete" : {
      "wmajority" :  NumberLong(<num>)
      "wnum" : {
         "<num>" :  NumberLong(<num>),
         ...
      },
      "wtag" : {
         "<tag1>" :  NumberLong(<num>),
         ...
      },
      "none" : NumberLong(<num>)
   }
}

opWriteConcernCounters

A document that reports on the write concerns specified by write operations to the mongod instance since it last started.

More specifically, the opWriteConcernCounters reports on the w: <value> specified by the write operations. The journal flag option (j) and the timeout option (wtimeout) of the write concerns does not affect the count. The count is incremented even if the operation times out.

Note

Only available when reportOpWriteConcernCountersInServerStatus parameter is set to true (false by default).

opWriteConcernCounters.insert

A document that reports on the w: <value> specified by insert operations to the mongod instance since it last started:

Note

Only available when reportOpWriteConcernCountersInServerStatus parameter is set to true (false by default).

"insert" : {
   "wmajority" : NumberLong(<num>),
   "wnum" : {
      "<num>" :  NumberLong(<num>),
      ...
   },
   "wtag" : {
      "<tag1>" :  NumberLong(<num>),
      ...
   },
   "none" : NumberLong(<num>)
},

Specified `w`	Description
`"wmajority"`	Number of insert operations that specified `w: "majority"`.
`"wnum"`	Number of insert operations that specified `w: <num>`. The counts are grouped by the specific``<num>``.
`"wtag"`	Number of insert operations that specified `w: <tag>`. The counts are grouped by the specific `<tag>`.
`"none"`	Number of insert operations that did not specify `w` value. These operations use the default `w` value of `1`.

The sum of the opWriteConcernCounters.insert equals opcounters.insert.

opWriteConcernCounters.update

A document that reports on the w: <value> specified by update operations to the mongod instance since it last started:

Note

Only available when reportOpWriteConcernCountersInServerStatus parameter is set to true (false by default).

"update" : {
   "wmajority" : NumberLong(<num>),
   "wnum" : {
      "<num>" :  NumberLong(<num>),
   },
   "wtag" : {
      "<tag1>" :  NumberLong(<num>),
      ...
   },
   "none" : NumberLong(<num>)
},

Specified `w`	Description
`"wmajority"`	Number of update operations that specified `w: "majority"`.
`"wnum"`	Number of update operations that specified `w: <num>`. The counts are grouped by the specific `<num>`.
`"wtag"`	Number of update operations that specified `w: <tag>`. The counts are grouped by the specific `<tag>`.
`"none"`	Number of update operations that did not specify `w` value. These operations use the default `w` value of `1`.

The sum of the opWriteConcernCounters.update equals opcounters.update.

opWriteConcernCounters.delete

A document that reports on the w: <value> specified by delete operations to the mongod instance since it last started:

Note

Only available when reportOpWriteConcernCountersInServerStatus parameter is set to true (false by default).

"delete" : {
   "wmajority" :  NumberLong(<num>)
   "wnum" : {
      "<num>" :  NumberLong(<num>),
      ...
   },
   "wtag" : {
      "<tag1>" :  NumberLong(<num>),
      ...
   },
   "none" : NumberLong(<num>)
}

Specified `w`	Description
`"wmajority"`	Number of delete operations that specified `w: "majority"`.
`"wnum"`	Number of delete operations that specified `w: <num>`. The counts are grouped by the specific `<num>`.
`"wtag"`	Number of delete operations that specified `w: <tag>`. The counts are grouped by the specific `<tag>`.
`"none"`	Number of delete operations that did not specify `w` value. These operations use the default `w` value of `1`.

The sum of the opWriteConcernCounters.delete equals opcounters.delete.

opcounters

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

"opcounters" : {
   "insert" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "query" : NumberLong(<num>),   // Starting in MongoDB 4.2, type is NumberLong
   "update" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "delete" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "getmore" : NumberLong(<num>), // Starting in MongoDB 4.2, type is NumberLong
   "command" : NumberLong(<num>), // Starting in MongoDB 4.2, type is NumberLong
},

opcounters

A document that reports on database operations by type since the mongod instance last started.

These numbers will grow over time until next restart. Analyze these values over time to track database utilization.

Note

The data in opcounters treats operations that affect multiple documents, such as bulk insert or multi-update operations, as a single operation. See metrics.document for more granular document-level operation tracking.

Additionally, these values reflect received operations, and increment even when operations are not successful.

opcounters.insert

The total number of insert operations received since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.query

The total number of queries received since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.update

The total number of update operations received since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.delete

The total number of delete operations since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.getmore

The total number of getMore operations since the mongod instance last started. This counter can be high even if the query count is low. Secondary nodes send getMore operations as part of the replication process.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.command

The total number of commands issued to the database since the mongod instance last started.

opcounters.command counts all commands except the write commands: insert, update, and delete.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.deprecated

This section only appears in the db.serverStatus() output when one of the following, deprecated opcodes has been used:

"deprecated": {
   "opQuery": NumberLong(<num>),
   "opGetMore": NumberLong(<num>),
   "opKillCursors": NumberLong(<num>),
   "opDelete": NumberLong(<num>),
   "opUpdate": NumberLong(<num>),
   "opInsert": NumberLong(<num>),
   "total": NumberLong(<num>),
}

These opcodes were deprecated in MongoDB 4.4.7 and support for these opcodes is removed in MongoDB 5.1. Starting in MongoDB 5.1, mongod refuses requests that use a deprecated opcode and increments the corresponding counter.

OP_QUERY is an exception to the general rule. mongod continues to support hello and isMaster requests that use OP_QUERY. mongod refuses any other OP_QUERY requests.

The counters are reset when mongod starts.

opcountersRepl

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

"opcountersRepl" : {
   "insert" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "query" : NumberLong(<num>),   // Starting in MongoDB 4.2, type is NumberLong
   "update" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "delete" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "getmore" : NumberLong(<num>), // Starting in MongoDB 4.2, type is NumberLong
   "command" : NumberLong(<num>), // Starting in MongoDB 4.2, type is NumberLong
},

opcountersRepl

A document that reports on database replication operations by type since the mongod instance last started.

These values only appear when the current host is a member of a replica set.

These values will differ from the opcounters values because of how MongoDB serializes operations during replication. See Replication for more information on replication.

These numbers will grow over time in response to database use until next restart. Analyze these values over time to track database utilization.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.insert

The total number of replicated insert operations since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.query

The total number of replicated queries since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.update

The total number of replicated update operations since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.delete

The total number of replicated delete operations since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.getmore

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.command

The total number of replicated commands issued to the database since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

oplogTruncation

"oplogTruncation" : {
   "totalTimeProcessingMicros" : <NumberLong>,
   "processingMethod" : <string>,
   "oplogMinRetentionHours" : <double>
   "totalTimeTruncatingMicros" : <NumberLong>,
   "truncateCount" : <NumberLong>
},

oplogTruncation

A document that reports on oplog truncations.

The field only appears when the current instance is a member of a replica set and uses either the WiredTiger Storage Engine or In-Memory Storage Engine.

Changed in version 4.4: Also available in In-Memory Storage Engine.

New in version 4.2.1: Available in the WiredTiger Storage Engine.

oplogTruncation.totalTimeProcessingMicros

The total time taken, in microseconds, to scan or sample the oplog to determine the oplog truncation points.

totalTimeProcessingMicros is only meaningful if the mongod instance started on existing data files (i.e. not meaningful for In-Memory Storage Engine).

See oplogTruncation.processingMethod

Changed in version 4.4: Also available in In-Memory Storage Engine.

New in version 4.2.1: Available in the WiredTiger Storage Engine.

oplogTruncation.processingMethod

The method used at start up to determine the oplog truncation points. The value can be either "sampling" or "scanning".

processingMethod is only meaningful if the mongod instance started on existing data files (i.e. not meaningful for In-Memory Storage Engine).

Changed in version 4.4: Also available in In-Memory Storage Engine.

New in version 4.2.1: Available in the WiredTiger Storage Engine.

oplogTruncation.oplogMinRetentionHours

New in version 4.4: The minimum retention period for the oplog in hours. If the oplog has exceeded the oplog size, the mongod only truncates oplog entries older than the configured retention value.

Only visible if the mongod is a member of a replica set and:

The mongod was started with the --oplogMinRetentionHours command line option or the storage.oplogMinRetentionHours configuration file option,
or
The minimum retention period was configured after startup using replSetResizeOplog.

oplogTruncation.totalTimeTruncatingMicros: The cumulative time spent, in microseconds, performing oplog truncations.
Changed in version 4.4: Also available in In-Memory Storage Engine.
New in version 4.2.1: Available in the WiredTiger Storage Engine.

oplogTruncation.truncateCount: The cumulative number of oplog truncations.
Changed in version 4.4: Also available in In-Memory Storage Engine.
New in version 4.2.1: Available in the WiredTiger Storage Engine.

repl

"repl" : {
   "hosts" : [
         <string>,
         <string>,
         <string>
   ],
   "setName" : <string>,
   "setVersion" : <num>,
   "ismaster" : <boolean>,
   "secondary" : <boolean>,
   "primary" : <hostname>,
   "me" : <hostname>,
   "electionId" : ObjectId(""),
   "rbid" : <num>,
   "replicationProgress" : [
         {
            "rid" : <ObjectId>,
            "optime" : { ts: <timestamp>, term: <num> },
            "host" : <hostname>,
            "memberId" : <num>
         },
        ...
   ]
}

repl: A document that reports on the replica set configuration. repl only appear when the current host is a replica set. See Replication for more information on replication.

repl.hosts: An array of the current replica set members' hostname and port information ("host:port").

repl.setName: A string with the name of the current replica set. This value reflects the --replSet command line argument, or replSetName value in the configuration file.

repl.ismaster: A boolean that indicates whether the current node is the primary of the replica set.

repl.secondary: A boolean that indicates whether the current node is a secondary member of the replica set.

repl.primary: The hostname and port information ("host:port") of the current primary member of the replica set.

repl.me: The hostname and port information ("host:port") for the current member of the replica set.

repl.rbid: Rollback identifier. Used to determine if a rollback has happened for this mongod instance.

repl.replicationProgress

An array with one document for each member of the replica set that reports replication process to this member. Typically this is the primary, or secondaries if using chained replication.

To include this output, you must pass the repl option to the serverStatus, as in the following:

db.serverStatus({ "repl": 1 })
db.runCommand({ "serverStatus": 1, "repl": 1 })

The content of the repl.replicationProgress section depends on the source of each member's replication. This section supports internal operation and is for internal and diagnostic use only.

repl.replicationProgress[n].rid: An ObjectId used as an ID for the members of the replica set. For internal use only.

repl.replicationProgress[n].optime: Information regarding the last operation from the oplog that the member applied, as reported from this member.

repl.replicationProgress[n].host: The name of the host in [hostname]:[port] format for the member of the replica set.

repl.replicationProgress[n].memberID: The integer identifier for this member of the replica set.

security

"security" : {
   "authentication" : {
      "mechanisms" : {
         "MONGODB-X509" : {
            "speculativeAuthenticate" : {
               "received" : <num>,
               "successful" : <num>
            },
            "authenticate" : {
               "received" : <num>,
               "successful" : <num>
            }
         },
         "SCRAM-SHA-1" : {
            "speculativeAuthenticate" : {
               "received" : <num>,
               "successful" : <num>
            },
            "authenticate" : {
               "received" : <num>,
               "successful" : <num>
            }
         },
         "SCRAM-SHA-256" : {
            "speculativeAuthenticate" : {
               "received" : <num>,
               "successful" : <num>
            },
            "authenticate" : {
               "received" : <num>,
               "successful" : <num>
            }
          }
       }
     },
     "SSLServerSubjectName": <string>,
     "SSLServerHasCertificateAuthority": <boolean>,
     "SSLServerCertificateExpirationDate": <date>
},

security

A document that reports on:

The number of times a given authentication mechanism has been used to authenticate against the mongod / mongos instance. (New in MongoDB 4.4)
The mongod / mongos instance's TLS/SSL certificate. (Only appears for mongod or mongos instance with support for TLS)

security.authentication.mechanisms: A document that reports on the number of times a given authentication mechanism has been used to authenticate against the mongod/mongos instance. The values in the document distinguish standard authentication and speculative authentication. [1]
New in version 4.4.
Note
The fields in the mechanisms document depend on the configuration of the authenticationMechanisms parameter. The mechanisms document includes a field for each authentication mechanism supported by your mongod / mongos instance.
The following example shows the shape of the mechanisms document for a deployment that only supports x.509 authentication.

security.authentication.mechanisms.MONGODB-X509

A document that reports on the number of times x.509 has been used to authenticate against the mongod / mongos instance.

Includes total number of x.509 authentication attempts and the subset of those attempts which were speculative. [1]

New in version 4.4.

security.authentication.mechanisms.MONGODB-X509.speculativeAuthenticate.received: Number of speculative authentication attempts received using x.509. Includes both successful and failed speculative authentication attempts. [1]
New in version 4.4.

security.authentication.mechanisms.MONGODB-X509.speculativeAuthenticate.successful: Number of successful speculative authentication attempts received using x.509. [1]
New in version 4.4.

security.authentication.mechanisms.MONGODB-X509.authenticate.received: Number of successful and failed authentication attempts received using x.509. This value includes speculative authentication attempts received using x.509.
New in version 4.4.

security.authentication.mechanisms.MONGODB-X509.authenticate.successful: Number of successful authentication attempts received using x.509. This value includes successful speculative authentication attempts which used x.509.
New in version 4.4.

[1]	(1, 2, 3, 4) Speculative authentication minimizes the number of network round trips during the authentication process to optimize performance.

security.SSLServerSubjectName: The subject name associated with the mongod / mongos instance's TLS/SSL certificate.

security.SSLServerHasCertificateAuthority

A boolean that is:

true when the mongod / mongos instance's TLS/SSL certificate is associated with a certificate authority.
false when the TLS/SSL certificate is self-signed.

security.SSLServerCertificateExpirationDate: The expiration date and time of the mongod / mongos instance's TLS/SSL certificate.

sharding

{
   "configsvrConnectionString" : "csRS/cfg1.example.net:27019,cfg2.example.net:27019,cfg2.example.net:27019",
   "lastSeenConfigServerOpTime" : {
      "ts" : Timestamp(1517462189, 1),
      "t" : NumberLong(1)
   },
   "maxChunkSizeInBytes" : NumberLong(67108864)
}

sharding: A document with data regarding the sharded cluster. The lastSeenConfigServerOpTime is present only for a mongos or a shard member, not for a config server.

sharding.configsvrConnectionString: The connection string for the config servers.

sharding.lastSeenConfigServerOpTime

The latest optime of the CSRS primary that the mongos or the shard member has seen. The optime document includes:

ts, the Timestamp of the operation.
t, the term in which the operation was originally generated on the primary.

The lastSeenConfigServerOpTime is present only if the sharded cluster uses CSRS.

sharding.maxChunkSizeInBytes: New in version 3.6.
The maximum size limit for a chunk. If the chunk size has been updated recently on the config server, the maxChunkSizeInBytes may not reflect the most recent value.

shardingStatistics

When run on a member of a shard:

"shardingStatistics" : {
   "countStaleConfigErrors" : NumberLong(<num>),
   "countDonorMoveChunkStarted" : NumberLong(<num>),
   "totalDonorChunkCloneTimeMillis" : NumberLong(<num>),
   "totalCriticalSectionCommitTimeMillis" : NumberLong(<num>),
   "totalCriticalSectionTimeMillis" : NumberLong(<num>),
   "countDocsClonedOnRecipient" : NumberLong(<num>),
   "countDocsClonedOnDonor" : NumberLong(<num>),
   "countRecipientMoveChunkStarted" : NumberLong(<num>),
   "countDocsDeletedOnDonor" : NumberLong(<num>),
   "countDonorMoveChunkLockTimeout" : NumberLong(<num>),
   "unfinishedMigrationFromPreviousPrimary" : NumberLong(<num>),
   "catalogCache" : {
      "numDatabaseEntries" : NumberLong(<num>),
      "numCollectionEntries" : NumberLong(<num>),
      "countStaleConfigErrors" : NumberLong(<num>),
      "totalRefreshWaitTimeMicros" : NumberLong(<num>),
      "numActiveIncrementalRefreshes" : NumberLong(<num>),
      "countIncrementalRefreshesStarted" : NumberLong(<num>),
      "numActiveFullRefreshes" : NumberLong(<num>),
      "countFullRefreshesStarted" : NumberLong(<num>),
      "countFailedRefreshes" : NumberLong(<num>)
   },
   "rangeDeleterTasks" : <num>
},

When run on a mongos:

"shardingStatistics" : {
   "numHostsTargeted": {
      "find" : {
         "allShards": NumberLong(<num>),
         "manyShards": NumberLong(<num>),
         "oneShard": NumberLong(<num>),
         "unsharded": NumberLong(<num>)
               },
      "insert": {
         "allShards": NumberLong(<num>),
         "manyShards": NumberLong(<num>),
         "oneShard": NumberLong(<num>),
         "unsharded": NumberLong(<num>)
               },
      "update": {
         "allShards": NumberLong(<num>),
         "manyShards": NumberLong(<num>),
         "oneShard": NumberLong(<num>),
         "unsharded": NumberLong(<num>)
               },
      "delete": {
         "allShards": NumberLong(<num>),
         "manyShards": NumberLong(<num>),
         "oneShard": NumberLong(<num>),
         "unsharded": NumberLong(<num>)
               },
      "aggregate": {
         "allShards": NumberLong(<num>),
         "manyShards": NumberLong(<num>),
         "oneShard": NumberLong(<num>),
         "unsharded": NumberLong(<num>)
               }
      }
   },
   catalogCache : {
      numDatabaseEntries : Long("<num>"),
      numCollectionEntries : Long("<num>"),
      countStaleConfigErrors : Long("<num>"),
      totalRefreshWaitTimeMicros : Long("<num>"),
      numActiveIncrementalRefreshes : Long("<num>"),
      countIncrementalRefreshesStarted : Long("<num>"),
      numActiveFullRefreshes : Long("<num>"),
      countFullRefreshesStarted : Long("<num>"),
      countFailedRefreshes : Long("<num>")
   }
},

shardingStatistics: A document which contains metrics on metadata refresh on sharded clusters.

shardingStatistics.countStaleConfigErrors

The total number of times that threads hit stale config exception. Since a stale config exception triggers a refresh of the metadata, this number is roughly proportional to the number of metadata refreshes.