Consistency group pair-split failures

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

• The pairs in the CTG are suspended (PSUE/SUSPER status).
• If the host server goes down or fails, there might be cases where a CTG is defined without any pairs. If this has happened and you are running the paircreate command with the CTG pair-split option, the command might be rejected.

  In this case, perform the following steps:

  1. Execute the raidcom get ctg command to find the CTG ID with the STS in CHG state.
  2. Specify the CTG ID that is not used by any pair in CCI.
  3. Create the pairs that will be the target of the CTG pair-split operation using the CCI of the host server.

• If the host server is down or has failed, many CTGs that contain no SIz 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 SIz pairs and re-execute the paircreate command:

  1. Execute the raidcom get ctg command to find the CTG ID with STS in CHG state.
  2. Specify the CTG ID that is not used by any pair using CCI.
  3. Create a SIz pair or a TIA pair that will be the target of the CTG pair-split operation using CCI on the host server.

     If the CTG ID is 128 or higher, you must create a TIA pair.

  4. Delete the SIz pair or TIA pair created in step 3.
• If you are using a URz S-VOL as an SIz 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.

  In this case, perform the following steps:

  1. Execute the raidcom get ctg command to find the CTG ID with STS in CHG state.
  2. Specify the CTG ID that is not used by any pair using CCI.
  3. Create a pair for the CTG pair-split by running the paircreate command on the host server.

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

  • The URz 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 SIz license is invalid.
  • The SIz pair volumes are blocked.
  • The SIz pair is in a status that does not allow you to run the pairsplit CCI command.
  • You are using an SIz pair volume in a TCz or URz pair, and the TCz or URz 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.