Unlike non-persistent FastResync, persistent FastResync keeps the FastResync maps on disk so that they can survive system reboots, system crashes and cluster crashes. Persistent FastResync can also track the association between volumes and their snapshot volumes after they are moved into different disk groups. When the disk groups are rejoined, this allows the snapshot plexes to be quickly resynchronized. This ability is not supported by non-persistent FastResync.
See "Reorganizing the contents of disk groups" on page 181.
If persistent FastResync is enabled on a volume or on a snapshot volume, a data change object (DCO) and a DCO volume are associated with the volume.