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MongoDB Ops Manager

FAQ: Backup and Restore

On this page

  • Requirements
  • What Version of MongoDB Does the Backup Feature Require?
  • What MongoDB Permissions does Backup Require?
  • How Does Ops Manager Measure Data Size?
  • Does Backup Work with All Types of Deployments?
  • Why Does The Backup Feature Not Support Standalone Deployments?
  • Operations
  • How Does The Backup Feature Work?
  • Will Backup Impact My Production Databases?
  • How Do I Maintain a Replica Set with Backup enabled?
  • Legacy Backup Agent
  • Where Should I Run The Backup Agent?
  • Can I Run the Backup and Monitoring Agents on a Single System?
  • Can I Run Multiple Backup Agents to Achieve High Availability?
  • Does the Backup Agent Modify My Database?
  • How Does the Initial Backup Sync Impact Database Performance?
  • Namespace Filters
  • How Can I Prevent Ops Manager from Backing Up a Collection?
  • How Can I Change which Namespaces Are Backed Up?
  • Data Restoration
  • How Does Ops Manager Provide Point-in-Time Restores?
  • Can I Take Snapshots More Frequently than Every 6 Hours?
  • Can I Set My Own Snapshot Retention Policy?
  • How Long Does It Take to Create a Restore Snapshot?
  • Does the Backup Feature Perform Any Data Validation?
  • How Do I Restore a Snapshot?
  • What Is Delivered when I Restore a Snapshot?
  • How Does Ops Manager Roll Back Backed-up Data?
  • What Conditions Require a Resync?

This FAQ addresses common questions about Ops Manager and how it backs up and restores databases and collections.

The introduction of the MongoDB Agent and the new backup process for MongoDB 4.2 with a FCV of 4.2 have changed some of these answers. Those answers have admonitions explaining the impact of these new features to existing answers.

Ops Manager Release Series
1.6 to 1.8
2.0 to 3.2
Minimum MongoDB 2.4 version
2.4.0 [1]
Minimum MongoDB 2.6 version
2.6.0 [2]
Minimum MongoDB 3.0 version
3.0.0 [2]
Minimum MongoDB 3.2 version
Minimum MongoDB 3.4 version
Minimum MongoDB 3.6 version
Minimum MongoDB 4.0 version
Minimum MongoDB 4.2 version
[1] Monitoring only
[2](1, 2) Monitoring and Backup only

If you are backing up a MongoDB instance that has authentication enabled, the MongoDB Agent requires the privileges described for the MongoDB Agent backup function.


See also:

Ops Manager uses the following conversions to measure snapshot size and to measure how much oplog data has been processed:

  • 1 MB = 1024 2 bytes (1 MiB)

  • 1 GB = 1024 3 bytes (1 GiB)

  • 1 TB = 1024 4 bytes (1 TiB)

  • For MongoDB 4.2 and later, see Backup Considerations for Databases.

  • For any MongoDB with FCV of 4.0 and earlier databases, Backup doesn't support standalone deployments. Backup has full support for replica sets and sharded clusters.

Ops Manager copies data from the oplog to provide a continuous backup with point-in-time recovery. Ops Manager does not support backup of standalone hosts because they do not have an oplog. To support backup with a single mongod instance, you can run a one-member replica set.

To learn about the Backup feature, see Backup Process.


This answer applies only to databases running MongoDB with FCV of 4.0 and earlier

The Backup feature typically has minimal impact on production MongoDB deployments. This impact performs similar to that of adding a new secondary to a replica set.

By default, the agent performs its initial sync, the most resource intensive operation for backups, against a secondary member of the replica set to limit its impact. You may optionally configure the Backup Agent to perform the initial sync against the replica set's primary, although this increases the impact of the initial sync operation.

Most operations in a replica set are replicated via the oplog and are thus captured by the backup process. Some operations, however, make changes that are not replicated: for these operations you must have Ops Manager resync from your current replica set to include the changes.

The following operations are not replicated and therefore require resync:

  • Renaming or deleting a database by deleting the data files in the data directory. As an alternative, remove databases using an operation that MongoDB will replicate, such as db.dropDatabase() from mongosh.

  • Changing any data while the instance is running as a standalone.

  • Rolling index builds.

  • Using compact or repairDatabase to reclaim a significant amount of space.

    Resync is not strictly necessary after compact or repairDatabase operations but will ensure that the Ops Manager copy of the data is resized, which means quicker restores.

Backup capability has been moved to the MongoDB Agent with Backup activated. This replaces the individual Backup Agent. This information covers issues unique to the legacy Backup Agent. All of this information applies to MongoDB databases running FCV of 4.0 or earlier.

Run the Backup Agent on a host that:

  • Is separate from your MongoDB instances. This avoids system resource contention.

  • Can connect to your MongoDB instances. Check network settings for connections between the agent and MongoDB hosts. For a list of needed ports, see open ports for agents.

  • Has at least 2 CPU cores and 3 GB of RAM above platform requirements. With each backup job it runs, the Backup Agent further impacts host performance.

There is no technical restriction that prevents the Backup Agent and the Monitoring from running on a single system or host. However, both agents have resource requirements, and running both on a single system can affect the ability of these agents to support your deployment in Ops Manager.

The resources required by the Backup Agent depend on rate and size of new oplog entries (i.e. total oplog gigabyte/hour produced.) The resources that the Monitoring requires depends on the number of monitored mongod instances and the total number of databases provided by the mongod instances.

You can run multiple Backup Agents for high availability. If you do, the Backup Agents must run on different hosts.

When you run multiple Backup Agents, only one agent per project is the primary agent. The primary agent performs the backups. The remaining agents are completely idle, except to log their status as standbys and to periodically ask Ops Manager whether they should become the primary.

The Backup Agent writes a small token called a checkpoint into the oplog of the source database at a regular interval. These tokens provide a heartbeat for backups and have no effect on the source deployment. Each token is less than 100 bytes.


You may use checkpoints for clusters that run MongoDB with Feature Compatibility Version of 4.0 or earlier. Checkpoints were removed from MongoDB instances with FCV of 4.2 or later.


See also:

The impact of the initial backup synchronization should be similar to syncing a new secondary replica set member. The Backup Agent does not throttle its activity, and attempts to perform the sync as quickly as possible.


Namespace filtering is supported only for Ops Manager versions 6.0.8 and later. Your MongoDB deployments must have featureCompatibilityVersion values of 4.0 and earlier, or 6.0.1 and later.

Ops Manager provides a namespaces filter that allows you to specify which collections or databases to back up.

To edit the filter, see Edit a Backup's Settings. Changing the namespaces filter might necessitate a resync. If so, Ops Manager handles the resync.

The most common reason that jobs fail to bind to a Backup Daemon is because no daemon has space for a local copy of the backed up replica set.

To increase capacity so that the backup job can bind, you can:

  • add an additional backup daemon.

  • increase the size of the file system that holds the head directory.

  • On FCV 4.0 and earlier, move the head database data to a new volume with more space, and create a symlink or configure the file system mount points so that the daemon can access the data using the original path.

    FCV 4.2 and later do not use head databases.

If you notice consistent errors in applyOps commands in your Backup logs, it may indicate that the daemon has run out of space.

To increase space on a daemon to support continued operations, you can:

  • increase the size of the file system that holds the head directory.

  • For FCV 4.0 and earlier, move the head database data to a new volume with more space, and create a symlink or configure the file system mount points so that the daemon can access the data using the original path.

    FCV 4.2 and later do not use head databases.

Ops Manager produces a copy of your data files that you can use to seed a new deployment.


Ops Manager 4.2.13 and later supports this feature with FCV of 4.2 or later.

When you trigger the restore, Ops Manager creates a link to this snapshot. Once clicked, Ops Manager retrieves chunks from the Snapshot Store and streams them to the target host.

The MongoDB Backup Restore Utility running on that host then downloads and applies oplog entries to reach the specified point in time.

The ability of Ops Manager to provide a given point-in-time restore depends on the retention policy of the snapshots and the configured point-in-time window.

To learn more about retention policy and the point-in-time window, see Edit Snapshot Schedule and Retention Policy.

No. Ops Manager does not support a snapshot schedule more frequent than every 6 hours. For more information, see Snapshot Frequency and Retention Policy.

Yes. You can change the schedule through the Edit Snapshot Schedule menu option for a backed-up deployment. Administrators can change the snapshot frequency and retention policy through the snapshotSchedule resource in the API.

Ops Manager transmits all backups in a compressed form from the Ops Manager host to your infrastructure.

In addition, point-in-time restores depend upon the amount the oplog entries that your host must apply to the received snapshot to roll forward to the requested point-in-time of the backup.

Backup conducts basic corruption checks and provides an alert if any component (e.g. the agent) is down or broken, but does not perform explicit data validation. When it detects corruption, Ops Manager errs on the side of caution and invalidates the current backup and sends an alert.

You can request a restore via Ops Manager, where you can then choose which snapshot to restore and how you want Ops Manager to deliver the restore. All restores require 2-factor authentication. If you have SMS set up, Ops Manager will send an authorization code via SMS. You must enter the authorization code into the backup interface to begin the restore process.


From India, use Google Authenticator for two-factor authentication. Google Authenticator is more reliable than authentication with SMS text messages to Indian mobile phone numbers (i.e. country code 91).

Ops Manager delivers restores as tar.gz archives of MongoDB data files.

To learn more about restores, see Restore MongoDB Deployments.


For MongoDB deployments running FCV 4.2 or later, rollbacks do not affect backed-up data in Ops Manager. From FCV 4.2 onward, Ops Manager only retains snapshots with timestamps up to and including the majority-commit point.

If your MongoDB deployment experiences a rollback, then Ops Manager also rolls back the backed-up data.

Ops Manager detects the rollback when a tailing cursor finds a mismatch in timestamps or hashes of write operations. Ops Manager enters a rollback state and tests three points in the oplog of your replica set's primary to locate a common point in history. Ops Manager rollback differs from MongoDB secondary rollback in that the common point does not necessarily have to be the most recent common point.

When Ops Manager finds a common point, the service invalidates oplog entries and snapshots beyond that point and rolls back to the most recent snapshot before the common point. Ops Manager then resumes normal backup operations.

If Ops Manager cannot find a common point, a resync is required.


This feature is incompatible with MongoDB 4.2 with FCV of 4.2.

If the Backup Agent's tailing cursor cannot keep up with your deployment's oplog, then you must resync your backups.

This scenario might occur if:

  • Your application periodically generates a lot of data, shrinking the primary's oplog window to the point that data is written to the oplog faster than Ops Manager can consume it.

  • If the Backup Agent is running on an under-provisioned or over-used machine and cannot keep up with the oplog activity.

  • If the Backup Agent is down for a period of time longer than the oplog size allows. If you bring down your agents, such as for maintenance, restart them in a timely manner. For more information on oplog size, see Replica Set Oplog in the MongoDB manual.

  • If you delete all replica set data and deploy a new replica set with the same name, as might happen in a test environment where deployments are regularly torn down and rebuilt.

  • If there is a rollback, and Ops Manager cannot find a common point in the oplog.

  • If an oplog event tries to update a document that does not exist in the backup of the replica set, as might happen if syncing from a secondary that has inconsistent data with respect to the primary.

  • If you create an index in a rolling fashion.


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