Consistency group pair-split failures

ShadowImage User Guide

Version
9.8.7
Audience
anonymous
Part Number
MK-98RD9021-17

If a consistency group (CTG) pair-split fails, note the following:

  • The pairs in the CTG are suspended (PSUE status).
  • If the host server is down or has failed, you can assign a pair to a CTG that is not associated with another SI pair. If you are using CCI to run commands under these conditions, do not run the paircreate command with CTG pair-split.

    In this case, perform the following steps:

    1. In the Local Replication window, select the Consistency Groups tab.
    2. In the Status column, locate a CTG ID that is not being used by any pairs.
    3. Use CCI to specify the CTG ID you found.
    4. Create a pair for CTG pair-split by running the paircreate command on the host server.
  • If the host server is down or has failed, many CTGs that contain no SI pair might be created and there might not be enough available CTGs. Under such conditions, if you are using CCI to run the paircreate command with CTG pair-split, the command might be rejected.

    In this case, perform the following steps to delete the CTG that contains no SI pair and rerun the paircreate command:

    1. In the Local Replication window, select the Consistency Groups tab.
    2. In the Status column, locate a CTG ID that is not being used by any pairs.
    3. Use CCI to explicitly specify the CTG ID you found.
    4. You can now create the SI pair or HTI pair for CTG pair-split by running the paircreate command on the host server.

      If the CTG ID is 128 or more, create an HTI pair. For more information about how to create an HTI pair, see the Hitachi Thin Image User Guide. If the pair is a Thin Image Advanced pair, see the Thin Image Advanced User Guide.

    5. Delete the SI pair or HTI pair created in step 2.
  • If you are using a UR S-VOL as an SI P-VOL and you are using CCI to run commands and the status for some pairs that are assigned to a CTG are not changed, some pairs remain unsplit in the CTG and pair consistency is not guaranteed after you run the pairsplit command.

    The following are possible reasons why the status for some pairs that are assigned to a CTG are not changed:

    • The UR pair is assigned to a CTG and the P-VOL and S-VOL have the same content. The journal volumes for this pair are full.
    • The SI license is invalid.
    • The SI pair volumes are blocked.
    • The SI pair is in a status that does not allow you to run the pairsplit CCI command.

      For more information about pair status, see Monitoring ShadowImage pair activity and status.

    • The SI pair is a part of cascaded pairs, and the other pairs in the cascaded pairs are in a status that does not allow you to split the pairs.

      For more information about L1 and L2 pair status and the pair tasks that you can perform on cascaded pairs, see L1, L2 pair status and supported pair tasks.

    • You are using an SI pair volume in a TC or UR pair, and the TC or UR pair is in a status that does not allow you to run the pairsplit CCI command.

    If you cannot change the status, the pairsplit CCI command can end abnormally with the error code EX_EWSTOT, which indicates timeout occurrence. You cannot change the pair status during a timeout.

    Remove these factors, and then complete the following steps:

    1. Resynchronize the pairs.
    2. Split the pairs.