Splitting ShadowImage pairs

ShadowImage User Guide

Part Number

Splitting an SI pair suspends the pairing of the P-VOL and S-VOLs until a resync or delete operation is performed. Host updates to the P-VOL continue and are tracked as delta tracks in the bitmap. The S-VOL data is available and can be accessed.

Splitting an SI pair ensures data consistency and that the data in the S-VOL at the time of the split is usable. The S-VOL contains a mirror image of the original volume at that point in time, and it is available for read/write access by secondary host applications.

The P-VOL for a split pair continues to be updated, but the S-VOL remains unchanged. The differential data that accrues while the pair is split is stored in the differential bitmaps. Changes to the P-VOL and S-VOLs are managed in these differential bitmaps. The differential data accrues until you resynchronize the pair, which copies the differential data to the S-VOL.

If you have assigned an SI P-VOL or S-VOL to a volume reserved for Volume Migration, splitting the volume cancels migration.

If you are splitting SI pairs with shared TC or UR volumes, see the restrictions (see Requirements_ restrictions_ and guidelines for using consistency group pair-split with shared volumes).

If you are sharing SI S-VOLs with UR P-VOLs and the R-JNL has a timeout period that ends after the split time, the storage system might not detect the journal data. In this case, the SI split operation runs after the timeout period.

You set the timeout value according to your requirements.

Default: 6 hours