Adding and removing volumes in a consistency group
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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.
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.
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.
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*
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
Delete the zero RTO consistency group relationship:
destination::>snapmirror delete -destination-path vs1_dst:vol_dst3
Release the source SnapMirror relationship and retain the common Snapshot copies:
source::>snapmirror release -relationship-info-only true -destination-path vs1_dst:vol_dst3
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
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
Resynchronize the zero RTO consistency group relationship to ensure it is in sync:
destination::>snapmirror resync -destination-path vs1_dst:/cg/cg_dst
Remap the LUNs that you unmapped in Step 5:
destination::> lun map -vserver vs1_dst -path <lun_path> -igroup <igroup_name>
Rescan host LUN I/O paths to restore all paths to the LUNs.