When you create a copy pair, the initial copy operation is performed to copy all of the data in the P-VOL to the S-VOL. Once the pair is synchronized, the primary storage system performs update copy operations when it receives write I/Os for the P-VOL. The update copy operation ensures that host updates are performed on the P-VOL and the S-VOL at the same time.
The following figure illustrates the initial copy and update copy operations.
