FlashCopy to Metro Mirror source volumes

You can use an existing Metro Mirror source volume as a FlashCopy target volume. This process allows you to create a point-in-time copy and then make a copy of that data at a remote site.

Previously, you could create a FlashCopy relationship between two volumes and then create a Metro Mirror volume pair by using the FlashCopy target volume as the Metro Mirror source volume. However, you could not use an existing Metro Mirror source volume as a FlashCopy target volume. This is no longer a restriction. You can create FlashCopy target volumes that serve as production volumes and mirror them to a remote site using the Metro Mirror function.

You can create a full volume or incremental point-in-time copy to an existing Metro Mirror source volume. The first time that you create a FlashCopy operation, the entire Metro Mirror source volume has to be copied to the remote site, like a new pair being established. Afterwards, provided that you created the FlashCopy volume pair with the persistent and change recording options, you can perform a refresh (incremental) operation of the FlashCopy relationship. The refresh operation copies only changes and sends them to the remote site, requiring less time for the remote mirror and copy volumes to be synchronized again.

When you create a FlashCopy operation and the logical copy finishes, the corresponding Metro Mirror volume pairs turn to the duplex pending status as long as the FlashCopy data is being transferred to the Metro Mirror remote site. The time it takes to complete the copy of the FlashCopy data, until all remote mirror and copy volumes are synchronous again, depends on the amount of data to be transferred and the available bandwidth to the remote site. Be aware that, during this time, the remote site will be inconsistent if a disaster occurs. Therefore, you must carefully decide if you can tolerate not mirroring FlashCopy target volumes temporarily at a remote site.