Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

To dissociate a version 0 DCO object, DCO volume and snap objects from the

volume, use the following command:

# vxassist [-g diskgroup] remove log volume logtype=dco

To upgrade the volume, use the following command:

# vxsnap [-g diskgroup] prepare volume [ndcomirs=number] \

[regionsize=size] [drl=on|sequential|off] \

[storage_attribute ...]

The ndcomirs attribute specifies the number of DCO plexes that are created

in the DCO volume. You should configure as many DCO plexes as there are

data and snapshot plexes in the volume. The DCO plexes are used to set up a

DCO volume for any snapshot volume that you subsequently create from the

snapshot plexes. For example, specify ndcomirs=5 for a volume with 3 data

plexes and 2 snapshot plexes.

The regionsize attribute specifies the size of the tracked regions in the

volume. A write to a region is tracked by setting a bit in the change map. The

default value is 64k (64KB). A smaller value requires more disk space for the

change maps, but the finer granularity provides faster resynchronization.

To enable DRL logging on the volume, specify drl=on (this is the default

setting). If you need sequential DRL, specify drl=sequential. If you do not

need DRL, specify drl=off.

To define the disks that can or cannot be used for the plexes of the DCO

volume, you can also specify vxassist-style storage attributes.

Adding traditional DRL logging to a mirrored volume

A traditional DRL log is configured within a DRL plex. A version 20 DCO volume

cannot be used in conjunction with a DRL plex. The version 20 DCO volume layout

includes space for a DRL log.

See “Preparing a volume for DRL and instant snapshots” on page 318.

To put dirty region logging (DRL) into effect for a mirrored volume, you must add

a log subdisk to that volume. Only one log subdisk can exist per plex.

To add DRL logs to an existing volume, use the following command:

# vxassist [-b] [-g diskgroup] addlog volume logtype=drl \

[nlog=n] [loglen=size]

If specified, the -b option makes adding the new logs a background task.

Administering volumes

Adding traditional DRL logging to a mirrored volume

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