Resynchronizing or restoring ShadowImage pairs

ShadowImage User Guide

Part Number

Use this task to resynchronize or restore split or suspended pairs.

Resynchronizing split pairs typically takes less time than resynchronizing suspended pairs (PSUE status). Split pairs typically contain much less accumulated differential data than the total amount of data in the P-VOL.

  • You can only resynchronize L2 pairs.
  • After performing a Quick Split, wait 20 seconds before a Normal Copy or Quick Resync resynchronization, otherwise the operation might end abnormally.
  • The pair resynchronization (Normal Resync or Reverse Copy) requires some time to check if the differential data exists even if there is no differential data. The amount of time to check the differential data takes longer as the volume capacity increases, and it might take 10 minutes or more for 256 TB.

If you are using CCI to run commands, run the following command to resynchronize split pairs (PSUS status): pairresync

  1. In the Explorer pane, click Storage Systems, expand the storage system tree, and then click Replication > Local Replication.
  2. In the Local Replication window, select the SI Pairs tab.
  3. On the SI Pairs tab, select the pair you want to resynchronize, and then click Resync Pairs.
  4. In the Resync Pairs window of the Resync Pairs wizard, complete the following steps:
    • For Resync Type, select the type of resynchronization you want to perform.


      - Normal Copy (Primary > Secondary) (default): A full forward resynchronization.

      - Quick Resync (Primary > Secondary): A partial forward resynchronization.

      - Reverse Copy (Secondary > Primary): A full restoration of the P-VOL from the S-VOL.

      - Quick Restore (Secondary > Primary): A partial restoration of the P-VOL from the S-VOL.

      For more information about the types of SI pair resynchronization you can use, including complete descriptions of the types, see Types of pair resynchronization.

    • For Copy Pace, select the rate at which you want the storage system to copy data.


      - Slower: Improved host server I/O performance but slower processing speed.

      - Medium (default): Average processing speed and host server I/O performance.

      - Faster: Faster processing speed but slower host server I/O performance.

      Note: The pace you select affects processing speed and host server I/O performance

      For more information about performance, see Performance planning for ShadowImage.

  5. Click Finish, and then confirm the settings.
  6. Accept the default task name or enter a unique name.
    You can enter up to 32 letters, numbers, and symbols, except the following:

    \ / : , ; * ? " < > |

  7. If you want to monitor the task after submitting it, select Go to tasks window for status.
  8. Click Apply to submit the task.
    The pairs are resynchronized and the volumes are paired (PAIR status).
    Note: If you are reverse resynchronizing and the task ends abnormally, the pair is suspended (PSUE status).

    For more information about the PSUE status, see Device Manager - Storage Navigator pair status names and descriptions.