Table of ContentsView in Frames

Reversing the data protection mirror relationship when disaster occurs

When disaster disables the source FlexVol volume of a data protection mirror 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 a data protection mirror relationship that has the source volume on one Storage Virtual Machine (SVM) and the destination volume on another SVM. The source and the destination clusters and source and destination SVMs are in peer relationships. The original source (the one disabled by the disaster) is vs1:volA and the original destination is vs2:volB.

All data from the last scheduled SnapMirror Snapshot copy before the source was disabled and all the data written to vs2:volB after it was made writeable is preserved. Any data written to vs1:volA between the last SnapMirror Snapshot copy and the time that vs1:volA was disabled is not preserved.

For information about retrieving data from Infinite Volumes during disaster recovery, see the Clustered Data ONTAP Infinite Volumes Management Guide.

Steps

  1. Temporarily make the original source volume a read-only destination volume and reverse the data protection mirror relationship to continue to serve data.
    If the source vs1:volA is recoverable and its data is intact, 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. On the new destination volume, vs1:volA, use the snapmirror create command to create the mirror relationship, but with vs2:volB as the new source and vs1:volA as the new destination.
      Example
      vs1::> snapmirror create vs2:volB vs1:volA -type DP
    4. If there are LUNs on the original source volume, vs1:volA, remove the mapping by using the lun unmap command.
    5. On the new destination volume, vs1:volA, use the snapmirror resync command to resynchronize vs1:volA with vs2:volB.
      Example
      vs1::> snapmirror resync vs1:volA 
    6. On the original 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
    7. On the original source volume, vs1:volA, use the snapmirror release command to remove relationship information from the source.
      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. 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
    4. On the source SVM, vs1, use the snapmirror release command to remove relationship information from the source.
      Even though the source volume is unrecoverable, the data protection mirror relationship still exists and must be removed.
      Example
      vs1::> snapmirror release vs2:volB
    5. Delete the old volume volA and use the volume create command to create a new data protection destination volume called vs1:volA.
      Note: Remember to use the -type DP parameter when creating the destination volume.
      Example
      vs1::> volume delete -volume vs1:volA
      vs1::> volume create -volume volA -aggr aggr1 
      -type DP -vserver vs1
    6. 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 vs2:volB vs1:volA -type DP
    7. 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
    8. 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 vs1:volA vs2:volB -type DP
  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.