MapR 5.0 Documentation : Creating Mirrors

A mirror is a read-only copy of an entire volume. Unlike snapshots, which are point-in-time images, mirrors are full read-only copies that can be kept synchronized with the source volume. Mirroring, which was previously impossible with Hadoop, lets you protect and manage data in several new ways:

  • Isolation - keep production data intact while letting a research team work with a separate read-only copy
  • Disaster recovery - mirror important data to a geographically separate cluster in another datacenter to provide continuity in the event of a disaster
  • Load balancing - create multiple mirrors within a cluster and load balance among them to parallelize high read volumes

Using the MapR Control System, you can quickly create a mirror of any volume on the cluster:

  1. Click the New Volume button to display the New Volume dialog.
  2. For the Volume Type, select Mirror Volume.
  3. Type the name of the original volume you created in the Mirror Source Volume field, followed by the @ symbol and the name of the cluster ("default"). For example, if you have created a volume called my-volume, type:
    my-volume@default
  4. In the Volume Name field, type a name for the mirror volume. Example: my-mirror
  5. In the Mount Path field, type a place to mount the volume. Example: /baz-mirror
  6. Click OK to create the mirror volume.