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Reversing the version-flexible SnapMirror relationship when disaster occurs

When disaster disables the source FlexVol volume of a version-flexible SnapMirror relationship, you can use the destination FlexVol volume to serve data while you repair or replace the source, update the source, and reestablish the original configuration of the systems.

About this task

The following procedure describes the following version flexible SnapMirror relationship:

All data from the last scheduled version-flexible SnapMirror Snapshot copy before the source was hit by the disaster and all the data written to the destination, vs2:volB, after it is made writeable during the procedure, is preserved. Any data written to vs1:volA between the last SnapMirror Snapshot copy and the time that vs1:volA was stricken is not preserved.

Steps

  1. Temporarily create a new SnapMirror relationship that uses the destination volume from the disaster-stricken SnapMirror relationship as the new source volume.

    This allows you the time to either reuse the stricken source volume, if it is recoverable, or create a new volume that can become the source volume, if it is not recoverable.

    If the source vs1:volA is recoverable and its data is intact, complete the following steps:

    1. Make the vs2:volB destination volume writeable by using the snapmirror break command.
      Example
      vs2::> snapmirror break vs2:volB
    2. Redirect the clients from the original vs1:volA source volume to the vs2:volB volume.
      This gives the former clients of the vs1:volA volume access and write capability to thevs2:volB volume. The vs2:volB volume will become the temporary source volume of a new SnapMirror relationship while you repair the original vs1:volA source volume.
    3. On the vs1:volA volume, , use the snapmirror create command to create the mirror relationship with vs2:volB as the source and vs1:volA as the destination.
      This SnapMirror relationship is the reverse of the original SnapMirror relationship and will replicate new data to the vs1:volA volume.
      Example
      This example uses the "MirrorLatest" policy, which retains only the latest SnapMirror created Snapshot copy.
      vs1::> snapmirror create -source-path vs2:volB 
      -destination-pathvs1:volA -type XDP -policy MirrorLatest
    4. If there are LUNs on the original source volume, vs1:volA, remove the mapping by using the lun unmap command.
    5. On the vs1:volA destination volume, use the snapmirror resync command to resynchronize vs1:volA with vs2:volB.
      Example
      vs1::> snapmirror resync vs1:volA 
    6. From the SVM that contains the vs2:volB volume, remove the original SnapMirror relationship between volumes by using the snapmirror delete command.
      Example
      vs2::> snapmirror delete vs2:volB
    7. From the SVM that contains the vs1:volA volume, remove the original SnapMirror relationship information and Snapshot copies by using the snapmirror release command.
      Example
      vs1::> snapmirror release vs2:volB
    8. If there were LUNs, map the LUNs on the new source vs2:volB by using the lun map command.
    If the source vs1:volA is unrecoverable, complete the following steps:
    1. After the source volume (in this case, vs1:volA) is disabled, use the snapmirror break command on the destination volume, vs2:volB, to make the destination volume, vs2:volB, writeable.
      Example
      vs2::> snapmirror break vs2:volB
    2. Redirect the clients of the source volume vs1:volA to the new source volume vs2:volB.
      The former clients of vs1:volA access and write to vs2:volB.
    3. Delete the old volA volume by using the volume delete command.
      Example
      vs1::> volume delete -volume vs1:volA
    4. Create a new SnapMirror destination volume called vs1:volA by using the volume create command with the -type DP parameter.
      Note: Remember to use the -type DP parameter when creating the destination volume.
      Example
      vs1::> volume create -volume volA -aggr aggr1 
      -type DP -vserver vs1
    5. On the new destination volume, vs1:volA, use the snapmirror create command to create the data protection mirror relationship with vs2:volB as the new source volume and vs1:volA as the new destination volume.
      Example
      vs1::> snapmirror create -source-path vs2:volB 
      -destination-path vs1:volA -type XDP -policy MirrorLatest
    6. On the new destination volume, vs1:volA, use the snapmirror initialize command to create the baseline on the data protection mirror copy.
      This command also makes vs1:volA a read-only destination.
      Example
      vs1::> snapmirror initialize vs1:volA
    7. On the destination volume, vs2:volB, use the snapmirror delete command to remove the data protection mirror relationship between the source vs1:volA and the destination vs2:volB.
      Example
      vs2::> snapmirror delete vs2:volB
    8. Remove relationship information from the vs1 SVM by using the snapmirror release command.
      Even though the source volume is unrecoverable, the data protection mirror relationship still exists and must be removed.
      Example
      vs1::> snapmirror release vs2:volB
    9. If there were LUNs, map the LUNs on the new source vs2:volB by using the lun map command.

    You can keep this configuration or, after resolving the problem with the original source volume, you can complete the following steps to reestablish the original data protection mirror relationship.

  2. On the new destination volume, vs1:volA, update the new destination volume vs1:volA to transfer the latest data from the new source volume vs2:volB by using the snapmirror update command.
    Example
    vs1::> snapmirror update vs1:volA
  3. On the new destination volume, vs1:volA, use the snapmirror break command to make vs1:volA writeable.
    Example
    vs1::>> snapmirror break -source-path vs2:volB 
    -destination-path vs1:volA
  4. On the original destination volume, vs2:volB, use the snapmirror create command to re-create the original data protection mirror relationship with vs1:volA as the source and vs2:volB as the destination.
    Example
    vs2::> snapmirror create -source-path vs1:volA 
    -destination-path vs2:volB -type XDP -policy MirrorLatest
  5. If there are LUNs on the source vs2:volB, remove the mapping by using the lun unmap command.
  6. On the original destination volume, vs2:volB, use the snapmirror resync command to resynchronize the original source and original destination volumes.
    Example
    vs2::> snapmirror resync vs2:volB 
  7. On the new destination volume, vs1:volA, use the snapmirror delete command to remove the data protection mirror relationship between the new source vs2:volB and the new destination vs1:volA.
    Example
    vs1::> snapmirror delete vs1:volA
  8. On the new source volume, vs2:volB, use the snapmirror release command to remove the data protection mirror relationship between the new source vs2:volB and the new destination vs1:volA.
    Example
    vs2::> snapmirror release vs1:volA
  9. Redirect the clients from vs2:volB back to their original source volumevs1:volA.
  10. If there were LUNs, map them back to the original source vs1:volA.