Changing Mirror Volumes to Standard Volumes

Describes how to convert a mirror volume to a standard volume.

About this task

To change read-only mirror volumes to read-write (standard) volumes, you must promote the mirror volumes to standard volumes. After the mirror volume is promoted, the snapshot schedule specified for the mirror is used for the promoted read-write volume and the mirror schedule is disabled. You can promote a mirror volume to a standard volume using the Control System or the CLI.

NOTE When you use promotable mirrors, the volumes on the destination cluster must be set up in the same way as on the primary site. This means that volume names are the same and mount points are the same. If a hierarchical mounting structure (such as /A/B) is used on the primary site, the same structure must be recreated once mirror volumes are promoted at the secondary site.

Mirror promotion time is typically negligible, but is dependent on the number of containers in the volume being promoted. For a volume with thousands of containers and a few terabytes of data, it may take a few seconds. For enormous volumes with tens of thousands of containers and hundreds of terabytes of data, promotion could take a few minutes.

After the promotion is complete, a status message is logged in the cldb.log file with the time taken. For example:
2021-06-27 22:47:00,563 INFO  VolumeMirrorInfo [VolumeMirrorThread0]: 
    Volume conversion successfully completed for volume v100k.m@c.228toMirror false. 
    Time taken : 142395ms

Changing Multiple Mirror Volumes to Standard Volumes Using the Control System

About this task

To change one or more mirror volumes to standard volumes, in the Summary tab under Data > Volumes:
NOTE The Summary tab is under the Volumes menu in the Kubernetes version of the Control System.

Procedure

  1. Select the mirror volumes to promote from the list of volumes in Volumes pane.
  2. Select Change to Standard Volume(s) from the Actions drop-down menu.
    The Change to Standard Volume(s) confirmation dialog displays.
  3. Review the list of mirror volumes to promote and click Change Volume(s) to change the mirror volumes to standard volumes.

What to do next

NOTE Mirror volumes that are promoted to standard (read-write) volumes are not available for write operations until they are mounted explicitly. For more information, see Handling Mount Points in Promoted Mirror Volumes.

Changing a Mirror Volume to a Standard Volume Using the Control System

Procedure

  1. Log in to the Control System and go to the volume information page for the mirror volume.
  2. Select Change to Standard Volume(s) from the Select Action drop-down menu.
    The Change to Standard Volume(s) confirmation dialog displays.
  3. Click Change Volume(s) to change the mirror volume to a standard volume.

What to do next

NOTE Mirror volumes that are promoted to standard (read-write) volumes are not available for write operations until they are mounted explicitly. For more information, see Handling Mount Points in Promoted Mirror Volumes.

Changing a Mirror Volume to a Standard Volume Using the CLI or REST API

About this task

For changing a mirror volume to a standard (read/write) volume using the CLI, run the maprcli volume modify command with the -type option value set to rw on the cluster where the mirror volume resides and specify the name of the mirror volume that is being promoted. In the following example, the mirror volume is named volA: 
Cluster2> maprcli volume modify -name volA -type rw

For more information, see volume modify.

What to do next

NOTE Mirror volumes that are promoted to standard (read-write) volumes are not available for write operations until they are mounted explicitly. For more information, see Handling Mount Points in Promoted Mirror Volumes.