Using a DCO and DCO volume with a RAID-5 volume

You can add a DCO and DCO volume to a RAID-5 volume. This lets you use Persistent FastResync on the volume for fast resynchronization of snapshots on returning them to their original volume. However, this procedure has the side effect of converting the RAID-5 volume into a special type of layered volume. You can create space-optimized instant snapshots of such a volume, and you can add mirrors that may be broken off as full-sized instant snapshots. You cannot relayout or resize such a volume unless you convert it back to a pure RAID-5 volume.

To convert a volume back to a RAID-5 volume, remove any snapshot plexes from the volume, and dissociate the DCO and DCO volume from the layered volume. You can then perform relayout and resize operations on the resulting non-layered RAID-5 volume.

To allow Persistent FastResync to be used with the RAID-5 volume again, re-associate the DCO and DCO volume.


Dissociating a DCO and DCO volume disables FastResync on the volume. A full resynchronization of any remaining snapshots is required when they are snapped back.

More Information

Removing support for DRL and instant snapshots from a volume

Preparing a volume for DRL and instant snapshots