Manage Oplog Storage
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Throughout the lifecycle of a backup, MongoDB Agent tails the oplog of each replica set and sends new oplog entries to Ops Manager. The Agent sends the oplog entries in compressed bundles of approximately 10 MB in size called oplog slices. These oplog slices are stored in one or more MongoDB databases called oplog stores. Every Ops Manager deployment needs at least one oplog store.
When you enable backups, Ops Manager prompts you to create your first oplog store. This can be a local oplog store or an S3-compatible oplog store. Once you create the first oplog store, you manage it separately from your snapshot stores. You can create additional oplog stores.
This tutorial covers creating additional Oplog Stores to store oplog entries. Like any MongoDB instance, Oplog Stores can exist on any host running MongoDB that the Ops Manager application can access.
Prerequisites
Before creating any Oplog Stores:
Ensure storage volume(s) with sufficient capacity to store the oplog MongoDB database are attached to the Ops Manager or MongoDB host.
Deploy the dedicated MongoDB instance(s) to host the oplog stores.
Ensure the host running the Ops Manager Backup Daemon service has sufficient capacity to store the head database.
Secure the instance that stores your Oplog Stores using authentication and TLS. Oplog stores support
all authentication mechanisms.
Procedures
The format of the Username and Password depend upon the authentication mechanism. Select one of the following tabs:
Add One Oplog Store
Navigate to the Oplog Storage page.
Click the Admin link.
Click the Backup tab.
(Optional) If you have not previously set the head directory, set it in the Head Directory box.
Click the Oplog Storage page.
Provide the Oplog Store details.
Field | Necessity | Action | |
|---|---|---|---|
Name | Required | Type the label for the Oplog Store. | |
Datastore Type | Required | Select Standalone, Replica Set or
Sharded Cluster. | |
MongoDB Host List | Conditional | Type a comma-separated list of For example: This field displays only if you set Datastore Type to Replica Set or Sharded Cluster. | |
MongoDB Hostname | Conditional | Type the hostname of the standalone MongoDB instance. This field displays only if you set Datastore Type to Standalone. | |
MongoDB Port | Conditional | Type the port number of the standalone MongoDB instance. This field displays only if you set Datastore Type to Standalone. | |
Username | Optional | If you set this value: Type the name of the user authorized to access the this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring SCRAM authentication, see SCRAM. Type the RFC-2253-formatted subject from the client certificate of the user authorized to access this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring x.509 authentication, see x.509. Type the UPN of the user authorized to access this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring Kerberos authentication, see Kerberos. Type the name of the LDAP user authorized to access this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring LDAP authentication, see LDAP. | |
Password | Optional | If you set this value: Type the password associated with the username that can access this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring SCRAM authentication, see SCRAM. Leave it blank. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring x.509 authentication, see x.509. Kerberos retrieves the password from its keytab file. Don't type a password into this field. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring Kerberos authentication, see Kerberos. Type the password of the LDAP user authorized to access this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring LDAP authentication, see LDAP. WARNING: If you did not use the credentialstool to encrypt this password, it is stored as plaintext in the database. | |
Connection Options | Optional | Type any additional connection string options for the MongoDB instance. This field supports unescaped values only. You must provide a value for the For proper syntax and examples, see Connection String URI Format in the MongoDB manual. | |
Encrypted Credentials | Optional | Select if the credentials for the database were encrypted
using the
credentialstool.
The credentials include the Username, Password, AWS Access
Key ID and AWS Secret Key. | |
Use TLS/SSL | Optional | Select if the Oplog Store database only accepts connection encrypted using TLS. Beyond this checkbox, to connect this oplog store using TLS, you must enable TLS on the oplog store database. | |
New Assignment Enabled | Optional | Select if you want to enable this Oplog Store after creating
it. This is selected by default so the Oplog Store can be
assigned backup jobs. If you clear this checkbox, the
Oplog Store is created but you cannot assign backups to this
Oplog Store. |
Edit One Existing Oplog Store
Ops Manager lists Oplog Stores in a table on the Oplog Storage page. Each row contains the settings for each local and S3-compatible storage oplog store.
Navigate to the Oplog Storage page.
Click the Admin link.
Click the Backup tab.
(Optional) If you have not previously set the head directory, set it in the Head Directory box.
Click the Oplog Storage page.
Update any values that need to be changed.
In the MongoDB Connection column, update any values that need to be changed in the following fields:
Field | Action | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
<hostname>:<port> | Type in one or more hosts that comprise the Oplog Store
database in the IMPORTANT: If these hosts are changed, the Oplog Store database they host must have the same data as the original Oplog Store database. Changing the host to a new Oplog Store database results in data loss. If the Oplog Store database is a Replica Set or Sharded
Cluster, type a comma-separated list of For example: If the Oplog Store database is a standalone MongoDB
instance, type the | ||||||||||||||||
MongoDB Auth Username | If you set this value: Type the name of the user authorized to access the this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring SCRAM authentication, see SCRAM. Type the RFC-2253-formatted subject from the client certificate of the user authorized to access this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring x.509 authentication, see x.509. Type the UPN of the user authorized to access this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring Kerberos authentication, see Kerberos. Type the name of the LDAP user authorized to access this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring LDAP authentication, see LDAP. | ||||||||||||||||
MongoDB Auth Password | If you set this value: Type the password associated with the username that can access this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring SCRAM authentication, see SCRAM. Leave it blank. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring x.509 authentication, see x.509. Kerberos retrieves the password from its keytab file. Don't type a password into this field. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring Kerberos authentication, see Kerberos. Type the password of the LDAP user authorized to access this database. If your Ops Manager Application Database uses authentication or TLS, you must have connections configured to the application database. To learn more, see Configure the Connections to the Application Database. To learn more about configuring LDAP authentication, see LDAP. Ops Manager doesn't display the existing MongoDB Auth Password. WARNING: If you did not use the credentialstool to encrypt this password, it is stored as plaintext in the database. | ||||||||||||||||
Encrypted Credentials | Select if the credentials for the database were encrypted
using the
credentialstool.
The credentials include the Username, Password, AWS Access
Key ID and AWS Secret Key. | ||||||||||||||||
Use TLS/SSL | Select if the Oplog Store database only accepts connection encrypted using TLS. Beyond this checkbox, to connect this oplog store using TLS, you must enable TLS on the oplog store database. | ||||||||||||||||
Connection Options | Type any additional connection string options for the MongoDB instance.
This field supports unescaped values only. | ||||||||||||||||
Assignment Labels | Type a comma-separated list of labels to assign the
Oplog Stores to specific projects. | ||||||||||||||||
Write Concern | Select your preferred Write Concern:
|
Optional: Restart Ops Manager instances if needed.
If you change any connection string values or the Write Concern, restart all the Ops Manager instances including those running Backup Daemons.
Warning
Modifying the connection string values or the Write Concern for an existing blockstore requires you to restart all Ops Manager components, including those only running the Backup Daemon to apply those changes. Connection parameters include:
<hostname>:<port>
MongoDB Auth Username
MongoDB Auth Password
Encrypted Credentials
Use TLS/SSL
Connection Options
Write Concern
If you change to another Oplog Store host, the data on the existing Oplog Store is not copied automatically to the other Oplog Store.
Tip
See also:
For more details on the MongoDB connection string URI, see Connection String URI Format in the MongoDB Manual.
Delete One Oplog Store
Navigate to the Oplog Storage page.
Click the Admin link.
Click the Backup tab.
(Optional) If you have not previously set the head directory, set it in the Head Directory box.
Click the Oplog Storage page.