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Veritas NetBackup for MongoDB Administrator's Guide

Last Published: 2020-02-11

Product(s): NetBackup (8.2)

Known limitations for MongoDB protection using NetBackup

The following table lists the known limitations for MongoDB protection using NetBackup:

Table: Known limitations

Limitation	Workaround
In a sharded MongoDB cluster that contains multiple mongos processes, before starting a restore and recover operation, only the mongos process on the restore destination for the Config Server Replica Set (CSRS) image should be running. Manually stop any other mongos processes in the cluster before starting a restore and recover operation. After recovery, reconfigure the mongos services to point to the recovered cluster. If mongos process is not shut down on all nodes except one, the additional mongos processes might conflict with the restore and recover operation, causing the data that is restored to be inaccessible via a connection to mongos.	In case the mongos processes are not shutdown before starting the restore and recovery, then after recovery you must manually shutdown the stale mongos processes and then restart all the recovered mongod and mongos processes under cluster.
You must start the MongoDB processes with an absolute path to the configuration files. You must use the absolute paths for the certificate files and the CA file as well. You must specify the absolute paths for the CA file, PEM file and Key Files as well.	N/A
If the authentication type that was present during backup changes and you run a recovery job that requires a different authentication, the recovery process might fail.	Ensure that the authentication type during recovery remains the same as the type used during the backup.
After running a backup if you rename the volume group or the logical volume, the subsequent backup might fail.	N/A
During recovery, ensure that you select only one full backup image and its relevant subsequent incremental images. If you select more than one image, the recovery may fail as the restored data could be corrupted.	N/A
After your recover the MongoDB cluster, the cluster information for only the restored node is available.	After the recovery process is complete, manually add the secondary nodes to the cluster. For more information, refer to the following article: add-members-to-the-replica-set
During the backup process, if the MongoDB import operation is running, it can become unresponsive. Avoid the MongoDB import operation during the backup or restore process.	N/A
During the restore process, "The restore was successfully initiated" popup is displayed, but the restore job does not start. This issue occurs when you enter the Application Server in both the Source Client and Destination Client in the BAR UI.	Ensure that Source Client and Destination Client are entered correctly. The Source Client must be the Application Server and the Destination Client must be the backup host.
If your environment has DNAT, ensure that the backup host or the restore host and all the MongoDB nodes are in the same private network.	N/A
The NetBackup for MongoDB plug-in does not support the command line bprestore options -w and -print_jobid.	N/A
MongoDB restores are not supported from the backup hosts. All the restore operations for MongoDB must be initiated from the NetBackup master.	N/A
If your restore job submission is not displaying the restore job, check if your destination node has a MongoDB plug-in installed on it.	N/A
If you restore the MongoDB database to a non-LVM location and then try to take a backup from this non-LVM location, the backup fails.	Restore the data to an LVM location and then try to take a backup of the restored data.
The NetBackup for MongoDB plug-in does not support hard or soft links in the data path folders. Do not add any hard or soft links that point to locations in a different logical volume or a non-logical volume. NetBackup cannot ensure that the data is consistent at the time of backups if you have hard or soft links in the data path folder. During the restore process, the hard or soft links are created as folders and not links.	N/A
When you cancel a child restore job during the MongoDB restore and recovery process, the thin client (mdbserver) is not removed immediately. The thin client is removed after the next restore operation.	N/A
MongoDB restore fails and displays error 2850.	Ensure that the destination host and port is valid and has the credentials configured using the tpconfig command and the credentials file. For more information, refer to the tar logs.
After recovery, the MongoDB shard node fails to restart manually and the following error is seen in the MongoDB logs: NoSuchKey: Missing expected field "configsvrConnectionString"	On the MongoDB shard where the problem occurs, start MongoDB in the maintenance mode and run the following method on the system.version collection in the admin database: use admin db.system.version.deleteOne ( { _id: "minOpTimeRecovery" } )
In a restore and recover operation containing one or more replica sets, replica set members are restored to the replica set using the default "cfg.members[#].host" value provided by rs.config(). If this value was previously updated from the default value, after the restore and recover completes, this value may need to be updated (for example, from shortname to FQDN), to match the original configuration.	Workaround: Log in to the replica set MongoDB cluster Use the following command to check the configuration: rs.conf() Use the following command to update the configuration for replica set: Update configuration for replica set member 0: cfg = rs.conf(); cfg.members[0].host = '<hostname.domain.com>: <port-number>'; rs.reconfig(cfg) Verify the changes using the following command: rs.conf() Repeat the steps for the other replica sets and the members, or just the replica set members.
Backup jobs fail and the following error codes are displayed: (50) client process aborted (1) The requested operation was partially successful (112) no files specified in the file list	Ensure that the backup windows for incremental backups are different for the same MongoDB cluster. The backup windows must not overlap each other for incremental backups for the same MongoDB cluster. Ensure that permissions are in place for the mdbserver location, oplog location, and snapshot mount location. For more information, See Using a non-root user as a host user. In a sharded MongoDB cluster environment, a 112 error can indicate that the mongos process is not running on the client defined in the backup policy.
After a restore and recovery operation, if you try to stop and restart the mongod or mongos services (service mongod stop or service mongod restart), the commands fail. This error occurs when the mongod or mongos processes are launched as service using the service or systemctl commands and not using a direct command.	Workaround: Stop the mongod or mongos services using alternative methods. For example, mongod -f /etc/mongod.conf --shutdown or *kill <PID>. After stopping the services, you can use the service* or systemctl commands again. Note: When you stop the services after restore and recovery, the .pid or .sock files remain when you shutdown the mongod or mongos processes. You must delete the files if the mongod or mongos services do not start after shutting them down. The default location of the .sock files is /tmp The default location of the .pid files is /var/run/mongodb/
Backup operation fails if a command that generates output in .bashrc is added. Backup fails with error 6646 and displays the following error: Error: Unable to communicate with the server.	Ensure that no output is generated by .bashrc (echo or any other output generating command). The output should not return STDERR or STDOUT when the shell is non-interactive.
When you select two full backup images and try to restore to a point-in-time image that is between the two full backup images, the latest full backup image is restored.	Workaround: During the restore and recovery operation, do not select more than one full backup image. For an effective point-in-time recovery, ensure that you run differential incremental backups of shorter duration.
Unable to see the restore job progress in the Activity Monitor.	Workaround: For compound restore jobs that use a non-master server as the restore host, you must use the Update Task List button to display the restore job progress in the Activity Monitor.
Backup fails with the following error: (6625) The backup host is either unauthorized to complete the operation or it is unable to establish a connection with the application server.	Workaround: On the server where MongoDB is intalled, ensure that `PasswordAuthentication` is not disabled in `/etc/ssh/sshd_config` file. Run the sudo service sshd restart command.
Backup fails with the following error: (6646) Unable to communicate with the server.	Workaround: Ensure that the backup host can access the defined port in `mongodb.conf` file or the default `mdbserver_port` (11000). There could be an error while copying the thin client files on the MongoDB server because of the following: Connectivity issues with the MongoDB server User does not have permissions to the location for copying the thin client files
The following error is displayed in the mdbserver logs: error-sudo: sorry, you must have a tty to run sudo	Workaround: To disable the requiretty option globally, in the `sudoers` file, replace Defaults requiretty with Defaults !requiretty. This action changes the global sudo configuration. You can change the sudo configuration for the user, group, or command. On the server where MongoDB is installed, add the host user, or group, or command in the `sudoers` file. Add *Defaults /path/to/my/bin* !requiretty Add Default <host_user> !requiretty**
The nbaapireq_handler log folder is not created on a Flex Container, even after running the mklogdir command.	Workaround: When a Flex Appliance is upgraded from version 8.1.2 to 8.2 and the Flex media server is used as backup host, then for logging the MongoDB plug-in restore logs create the nbaapireq_handler folder in the /usr/openv/netbackup/logs/ directory.
MongoDB Restore fails with the error 2850	The target database path does not exist and there are insufficient permissions for the non-root user. Workaround: Ensure that the target database path exists and there are sufficient permissions for the non-root user.
The snapshot size as described by the free_space_percentage_snapshot parameter must be set according the MongoDB cluster size and must be large enough. If these criteria are not met, the backup fails and displays the following error: invalid command parameter (20)	Validate the free_space_percentage_snapshot value with the MongoDB cluster.