Adding Logs to a Volume

To add logs to a volume, use the following command:

The supported log types are dcm, dco, drl and raid5.

Adding a data change object (DCO) and DCO plex to a volume also allows the use of instant snapshots and dirty region logging (DRL) with the volume.

Traditional DRL may be added by specifying logtype=drl instead of logtype=dco. Such logs are implemented using a dedicated plex for each log copy, rather than using a DCO volume, and are supported for mirrored volume layouts only.

Data change map (DCM) logs are used with VERITAS Volume Replicator (VVR) replicated volumes. This type of log is usually added automatically by VVR adminstration commands.

RAID-5 logs are supported for software RAID-5 volumes only.

By default, one log or a DCO with one plex is added. You can use the nlogs attribute to specify the number of logs or DCO plexes to add. The loglen attribute can be used to specify the size of a RAID-5 log or a DCO volume. If the volume already contains such a log or DCO volume, this attribute is ignored. For a DCO volume, ISP may round up the length to make room for the maps that are required. For a RAID-5 log, a minimum size of three times the full stripe width is imposed, and the length is rounded up to a integral multiple of the full stripe width.

You can use storage attributes to specify the storage to be used for the logs. For example, the following command adds a DCO plex to the volume, mirvol1, using disk enc1_7: