Adding and removing volumes in a consistency group

Download PDF of this page

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.

About this task
  • The composition change is not allowed when the consistency group 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

This procedure assumes that there are 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. Verify that a common Snapshot copy exists between the source and destination volumes on both the source and destination cluster:

    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_dst2

  3. Delete the zero RTO 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. Create the new consistency group 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

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

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

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

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

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