Working with Mirror Volumes

A mirror volume is a read-only physical copy of another volume, the source volume. You can use mirror volumes in the same cluster (local mirroring) to provide local load balancing by using mirror volumes to serve read requests for the most frequently accessed data in the cluster. You can also mirror volumes on a separate cluster (remote mirroring) for backup and disaster readiness purposes.

For information about "promoting" mirror volumes to to read-write mode, see Using Promotable Mirrors.

Once you've created a mirror volume, keeping your mirror synchronized with its source volume is fast. Because mirror operations are based on a snapshot of the source volume, your source volume remains available for read and write operations for the entire duration of the process.

Note: Auditing of filesystem and table operations within volumes needs to be enabled at three separate levels, as described in Levels of Auditing for Filesystem, Table, and Stream Operations. The different levels at which auditing needs to be enabled are at the cluster, individual volumes, and individual objects within volumes. Auditing does not take place unless it is enabled at all three levels.

Auditing at the volume level is not enabled on remote mirror volumes even if it is enabled on their source volumes. You must run the volume audit command to enable auditing at the volume level for a remote mirror volume. Auditing at the object level for particular directories, files, and MapR-DB tables in a remote mirror volume is enabled automatically if auditing is enabled for them in the source volume. For full details about auditing, see Auditing of Cluster Administration and Operations on Directories, Files, Tables, and Streams.

The following sections provide information about how to work with mirror volumes: