Sharing volumes with TrueCopy

You can share SI P-VOLs and S-VOLs with TC P-VOLs and S-VOLs. However, you cannot share SI S-VOLs with TC S-VOLs.

The write operation on the TC P-VOL takes more time when you share an SI P-VOL with a TC S-VOL. Especially when the SI pair is in PSUP/SUSPVS status, the write operation takes more time because of the copy processing for the SI pair.

For more information about splitting pairs, see Other pair splitting methods.

Restrictions

The following restrictions apply:

• When you share an SI P-VOL with a TC S-VOL, if you split the SI pair during write I/Os to the TC P-VOL, only part of write I/Os might be written to the SI S-VOL. To keep data consistency in the SI S-VOL, stop I/Os to the TC P-VOL first, and then split the SI pair.
• You can use SI cascaded pairs as TC pairs. TC does not distinguish between node and leaf volumes in cascaded pairs. Both are considered S-VOLs.
• (VSP One B85) If you plan to Quick Restore the SI pair, you must first suspend the TC pair.
• You can perform a CTG pair-split on SI pairs that share volumes with TC S-VOLs.

  For more information about CTG pair-split for shared volumes, see Using consistency group pair-split with shared volumes

• If you want to use the SI S-VOL as the TIA P-VOL, create the SI pair first, and then create the TIA pair.
• (VSP One Block 85) If you request splitting all SI pairs in the same consistency group, the request is accepted only when all associated TC pairs are in PAIR, PSUS, or PSUE status. If the associated TC pairs are not in any of these statuses, the status of the SI pairs in the consistency group does not change. For details about whether SI pairs can be split using consistency group pair-split for each TC pair status, see Using consistency group pair-split with shared volumes.

For more information about sharing SI and TC volumes, see the TrueCopy^® User Guide for VSP One Block.

The following table describes ShadowImage operations when SI P-VOLs are shared with TC P-VOLs or S-VOLs.

The following table describes ShadowImage operations when SI S-VOLs are shared with TC P-VOLs.