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Modify member volumes in a consistency group

Contributors netapp-ahibbard

Beginning with ONTAP 9.12.1, you can modify a consistency group by removing volumes or adding volumes (expanding the consistency group). Beginning with ONTAP 9.13.1, you can move volumes between child consistency groups if they share a common parent.

Add volumes to a consistency group

Beginning with ONTAP 9.12.1, you can non-disruptively add volumes to a consistency group.

About this task
  • You cannot add volumes associated with another consistency group.

  • Consistency groups support NAS, SAN, and NVMe protocols.

  • You can add up to 16 volumes at a time to a consistency group if the adjustments are within the overall consistency group limits.

  • Beginning with ONTAP 9.13.1, you can non-disruptively add volumes to a consistency group with an active SnapMirror Business Continuity (SM-BC) or asynchronous SnapMirror protection policy.

  • When you add volumes to a consistency group protected by SM-BC, the status of the SM-BC relationship status will change to "Expanding" until mirroring and protection are configured for the new volume. If a disaster occurs on the primary cluster before this process completes, the consistency group reverts back to its original composition as part of the failover operation.

  • In ONTAP 9.12.1 and earlier, you cannot add volumes to a consistency group in an SM-BC relationship. You must first break the SM-BC relationship, modify the consistency group, then restore protection with SM-BC.

  • Beginning with ONTAP 9.12.1, the ONTAP REST API supports adding new or existing volumes to a consistency group. For more information about the ONTAP REST API, refer to ONTAP REST API reference documentation.

    Beginning with ONTAP 9.13.1, this functionality is supported in System Manager.

  • When expanding a consistency group, Snapshot copies of the consistency group captured before the modification will be considered partial. Any restore operation based on that Snapshot copy will reflect the consistency group at the point-in-time of the snapshot.

  • If you are using ONTAP 9.10.1 through 9.11.1, you cannot modify a consistency group. To change the configuration of a consistency group in ONTAP 9.10.1 or 9.11.1, you must delete the consistency group, then create a new consistency group with the volumes you want to include.

  • Beginning with ONTAP 9.14.1, you can replicate volume-granular Snapshots to the destination cluster when using Asynchronous SnapMirror. When expanding a consistency group using Asynchronous SnapMirror, volume-granular Snapshots are only replicated after expanding the consistency group when the SnapMirror policy is MirrorAll or MirrorAndVault. Only volume-granular Snapshots newer than the baseline consistency group Snapshot are replicated.

  • If you add volumes to a consistency group in an SVM disaster recovery relationship (supported beginning with ONTAP 9.14.1), you must update the SVM disaster recovery relationship from the destination cluster after expanding the consistency group. For more information, see see Update a replication relationship manually.

Example 1. Steps
System Manager

Beginning with ONTAP 9.12.1, you can perform this operation with System Manager.

  1. Select Storage > Consistency groups.

  2. Select the consistency group that you want to modify.

  3. If you are modifying a single consistency group, at the top of the Volumes menu, select More and then Expand to add a volume.

    If you are modifying a child consistency group, identify the parent consistency group you want to modify. Select the > button to view the child consistency groups, then select three vertically stacked dots next to the name of the child consistency group you want to modify. From that menu, select Expand.

  4. Select up to 16 volumes to add to the consistency group.

  5. Select Save. When the operation completes, view the newly added volumes in the consistency group's Volumes menu.

CLI

Beginning with ONTAP 9.14.1, you can add volumes to a consistency group using the ONTAP CLI.

Add existing volumes
  1. Issue the following command. The -volumes parameter accepts a comma-separated list of volumes.

    Note Only include the -parent-consistency-group parameter if the consistency group is in an hierarchical relationship.

    consistency-group volume add -vserver svm_name -consistency-group consistency_group_name -parent-consistency-group parent_consistency_group -volume volumes

Add new volumes

The procedure to add new volumes depends on the protocol you are using.

Note Only include the -parent-consistency-group parameter if the consistency group is in an hierarchical relationship.
  • To add new volumes without exporting them:

    consistency-group volume create -vserver SVM_name -consistency-group child_consistency_group -parent-consistency-group existingParentCg -volume volume_name -size size

  • To add new NFS volumes:

    consistency-group volume create -vserver SVM_name -consistency-group consistency-group-name -volume volume-prefix -volume-count number -size size -export-policy policy_name

  • To add new SAN volumes:

    consistency-group volume create -vserver SVM_name -consistency-group consistency-group-name -lun lun_name -size size -lun-count number -igroup igroup_name

  • To add new NVMe namespaces:

    consistency-group volume create -vserver SVM_name -consistency-group consistency_group_name -namespace namespace_name -volume-count number -namespace-count number -size size -subsystem subsystem_name

Remove volumes from a consistency group

Volumes removed from a consistency group are not deleted. They remain active in the cluster.

About this task
  • You cannot remove volumes from a consistency group in a SM-BC or SVM disaster recovery relationship. You must first break the SM-BC relationship to modify the consistency group and then reestablish the relationship.

  • If a consistency group has no volumes in it following the remove operation, the consistency group will be deleted.

  • When a volume is removed from a consistency group, existing Snapshots of the consistency group remain but are considered invalid. The existing Snapshots cannot be used to restore the contents of the consistency group. Volume-granular Snapshots remain valid.

  • If you delete a volume from the cluster, it is automatically removed from the consistency group.

  • To change the configuration of a consistency group in ONTAP 9.10.1 or 9.11.1, you must delete the consistency group then create a new consistency group with the desired member volumes.

  • Deleting a volume from the cluster will automatically remove it the consistency group.

System Manager

Beginning with ONTAP 9.12.1, you can perform this operation with System Manager.

Steps
  1. Select Storage > Consistency groups.

  2. Select the single or child consistency group that you want to modify.

  3. In the Volumes menu, select the checkboxes next to the individual volumes you want to remove from the consistency group.

  4. Select Remove volumes from the consistency group.

  5. Confirm that you understand removing the volumes will cause all Snapshot copies of the consistency group to become invalid and select Remove.

CLI

Beginning with ONTAP 9.14.1, you can remove volumes from a consistency group using the CLI.

Step
  1. Remove the volumes. The -volumes parameter accepts a comma-separated list of volumes.

    Only include the -parent-consistency-group parameter if the consistency group is in an hierarchical relationship.

    consistency-group volume remove -vserver SVM_name -consistency-group consistency_group_name -parent-consistency-group parent_consistency_group_name -volume volumes

Move volumes between consistency groups

Beginning with ONTAP 9.13.1, you can move volumes between child consistency groups that share a parent.

About this task
  • You can only move volumes between consistency groups nested under the same parent consistency group.

  • Existing consistency group Snapshots become invalid and no longer accessible as consistency group snapshots. Individual volume Snapshots remain valid.

  • Snapshot copies of the parent consistency group remain valid.

  • If you move all volumes out of a child consistency group, that consistency group will be deleted.

  • Modifications to a consistency group must abide by consistency group limits.

System Manager

Beginning with ONTAP 9.12.1, you can perform this operation with System Manager.

Steps
  1. Select Storage > Consistency groups.

  2. Select the parent consistency group that contains the volumes you want to move. Find the child consistency group and then expand the Volumes menu. Select the volumes you want to move.

  3. Select Move.

  4. Choose whether you want to move the volumes to a new consistency group or an existing group.

    1. To move to an existing consistency group, select Existing child consistency group then choose the consistency group's name from the dropdown menu.

    2. To move to a new consistency group, select New child consistency group. Enter a name for the new child consistency group and select a component type.

  5. Select Move.

CLI

Beginning with ONTAP 9.14.1, you can move volumes between consistency groups using the ONTAP CLI.

Move volumes to a new child consistency group
  1. The following command creates a new child consistency group that contains the designated volumes.

    When you create the new consistency group, you can designate new Snapshot, QoS, and tiering policies.

    consistency-group volume reassign -vserver SVM_name -consistency-group source_child_consistency_group -parent-consistency-group parent_consistency_group -volume volumes -new-consistency-group consistency_group_name [-snapshot-policy policy -qos-policy policy -tiering-policy policy]

Move volumes to an existing child consistency group
  1. Reassign the volumes. The -volumes parameter accepts a comma-separated list of volume names.

    consistency-group volume reassign -vserver SVM_name -consistency-group source_child_consistency_group -parent-consistency-group parent_consistency_group -volume volumes -to-consistency-group target_consistency_group