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Add or remove volumes to a consistency group

Contributors netapp-ahibbard netapp-thomi netapp-aherbin netapp-lenida
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As your application workload requirements change, you may need to add or remove volumes from a consistency group to ensure business continuity. The process of adding and removing volumes in an an active SM-BC relationship depends on the version of ONTAP you are using.

In most instances, this is a disruptive process requiring you to break the SnapMirror relationship, modify the consistency group, then resume protection. Beginning with ONTAP 9.13.1, adding volumes to a consistency group with an active SM-BC relationship is a non-disruptive operation.

About this task

  • In ONTAP 9.8 through 9.9.1, you can add or remove volumes to a consistency group using the ONTAP CLI.

  • Beginning with ONTAP 9.10.1, it is recommended that you manage consistency groups through System Manager or with the ONTAP REST API.

    If you want to change the composition of the consistency group by adding or removing a volume, you must first delete the original relationship and then create the consistency group again with the new composition.

  • Beginning in ONTAP 9.13.1, you can non-disruptively add volumes to a consistency group with an active SM-BC relationship from the source or destination.

    Removing volumes is a disruptive operation. You must break the SnapMirror relationship before proceeding removing volumes.

ONTAP 9.8-9.13.0
Before you begin

  • You cannot begin to modify the consistency group while it is in the InSync state.

  • The destination volume should be of type DP.

  • The new volume you add to expand the consistency group must have a pair of common Snapshot copies between the source and destination volumes.

Steps

The examples shown in two volume mappings: vol_src1 ←→ vol_dst1 and vol_src2 ←→ vol_dst2, in a consistency group relationship between the end points vs1_src:/cg/cg_src and vs1_dst:/cg/cg_dst.

  1. On the source and destination clusters, verify there is a common Snapshot between the source and destination clusters with the command snapshot show -vserver svm_name -volume volume_name -snapshot snapmirror

    source::>snapshot show -vserver vs1_src -volume vol_src3 -snapshot snapmirror*

    destination::>snapshot show -vserver vs1_dst -volume vol_dst3 -snapshot snapmirror*

  2. If no common Snapshot copy exists, create and initialize a FlexVol SnapMirror relationship:

    destination::>snapmirror initialize -source-path vs1_src:vol_src3 -destination-path vs1_dst:vol_dst3

  3. Delete the consistency group relationship:

    destination::>snapmirror delete -destination-path vs1_dst:vol_dst3

  4. Release the source SnapMirror relationship and retain the common Snapshot copies:

    source::>snapmirror release -relationship-info-only true -destination-path vs1_dst:vol_dst3

  5. Unmap the LUNs and delete the existing consistency group relationship:

    destination::>lun mapping delete -vserver vs1_dst -path <lun_path> -igroup <igroup_name>

    Note The destination LUNs are unmapped, while the LUNs on the primary copy continue to serve the host I/O.

    destination::>snapmirror delete -destination-path vs1_dst:/cg/cg_dst

    source::>snapmirror release -destination-path vs1_dst:/cg/cg_dst -relationship-info-only true

  6. If you are using ONTAP 9.10.1 through 9.13.0, delete and recreate and the consistency group on the source with the correct composition. Follow the steps in Delete a consistency group and then Configure a single consistency group. In ONTAP 9.10.1 and later, you must perform the delete and create operations in System Manager or with the ONTAP REST API; there is no CLI procedure.

    If you are using ONTAP 9.8, 9.0, or 9.9.1, skip to the next step.

  7. Create the new consistency group on the destination with the new composition:

    destination::>snapmirror create -source-path vs1_src:/cg/cg_src -destination-path vs1_dst:/cg/cg_dst -cg-item-mappings vol_src1:@vol_dst1, vol_src2:@vol_dst2, vol_src3:@vol_dst3

  8. Resynchronize the zero RTO consistency group relationship to ensure it is in sync:

    destination::>snapmirror resync -destination-path vs1_dst:/cg/cg_dst

  9. Remap the LUNs that you unmapped in Step 5:

    destination::> lun map -vserver vs1_dst -path lun_path -igroup igroup_name

  10. Rescan host LUN I/O paths to restore all paths to the LUNs.

ONTAP 9.13.1 and later

Beginning in ONTAP 9.13.1, you can non-disruptively add volumes to a consistency group with an active SM-BC relationship. SM-BC supports adding volumes from both the source or destination.

For details on adding volumes from the source consistency group, see Modify a consistency group.

Add a volume from the destination cluster

  1. On the destination cluster, select Protection > Relationships.

  2. Find the SM-BC relationship you want to add volumes to. Select kebab icon then Expand.

  3. Select the volume relationships whose volumes are to be added to consistency group

  4. Select Expand.