Functional Overview¶
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Overview¶
The MongoDB Management Service (MMS) is a service for monitoring and backing up a MongoDB infrastructure.
MMS Monitoring¶
MMS provides real-time reporting, visualization and alerting on key database and hardware indicators and presents the data in an intuitive web dashboard.
A lightweight Monitoring Agent runs within your infrastructure and connects to the configured MongoDB instances. The Monitoring Agent collect statistics from the nodes in your deployment and transmit it back to MMS. The MMS user interface allowsthe user to view the visualized data and set alerts.
MMS Backup¶
Engineered specifically for MongoDB, MMS Backup features scheduled snapshots and point in time recovery. Once the service is up and running, MMS provides a web interface to support backup and restoration. MMS Backup supports horizontal scaling.
A lightweight Backup Agent runs within your infrastructure and connects to the configured MongoDB instances. The agent performs an initial sync and then tails the oplog of a replica set’s primary. For a sharded cluster, the Backup Agent tails the primary of each shard and each config server. The agent ships initial sync and oplog data over HTTPS back to the MMS Backup service.
Operations¶
The MMS Backup service recreates every replica set you back up and applies the oplog entries sent by the Backup Agents. MMS then maintains a standalone MongoDB database on disk, also called a head, for each backed-up replica set. Each head is consistent with the original primary up to the last oplog supplied by the agent.
Backup performs the initial sync and the tailing of the oplog using standard MongoDB queries. The production replica set is not aware of the copy of the backup data.
The Backup service uses a mongod with a version equal to or greater than the version of the replica set it backs up.
The service retains snapshots based on a user-defined policy.
Sharded clusters snapshots temporarily stop the balancer via the mongos so that they can insert a marker token into all shards and config servers in the cluster. MMS takes a snapshot when the marker tokens appear in the backup data.
Compression and block-level deduplication technology reduces snapshot data size. The snapshot only stores the differences between successive snapshots. Snapshots use only a fraction of the disk space required for full snapshots.
Restores¶
MMS Backup lets you restore data from a scheduled snapshot or from a selected checkpoint or point in time between snapshots. Sharded clusters use checkpoints, and replica sets use point-in-time restores.
When you restore from a snapshot, MMS reads directly from the Backup Blockstore Database and transfers files via an HTTPS download link (pull) or by the MMS service sending files via SSH (push).
When you restore from checkpoint or point in time, MMS first creates a local restore of a snapshot from the blockstore. MMS then applies stored oplogs until the specified point. MMS delivers the backup via the same HTTPS or SSH mechanisms.
The amount of oplog to keep per backup is configurable and affects the time window available for checkpoint and point-in-time restores.