Full Mirror Resync

When a new submirror is attached (added) to a mirror, all the data from another submirror in the mirror is automatically written to the newly attached submirror. Once the mirror resync is done, the new submirror is readable. A submirror remains attached to a mirror until it is explicitly detached.

If the system crashes while a resync is in progress, the resync is started when the system reboots and comes back up.