VERITAS Storage Foundation 4.1 Intelligent Storage Provisioning Administrator's Guide

Chapter 4, Administering Application Volumes
Evacuating a Volume
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The value of 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=yes. If sequential DRL is required, specify
drl=sequential.
You can also specify vxvoladm-style storage attributes to define the disks that can and/or cannot
be used for the plexes of the DCO volume.
Removing Support for DRL and Snapshots from a Volume
To remove support for DCO-based DRL and instant snapshots from a volume, use the following
command to remove the DCO and DCO volume that are associated with the volume:
# vxvoladm [-g diskgroup] [-p storage_pool] removeall log volume \
logtype=dco
Note This command fails if the volume is part of a snapshot hierarchy.
Evacuating a Volume
If you need to remove or disable a disk, you must first move any data off the disk by evacuating it.
Similarly, if the whole or parts of a volume are configured on disks that are needed for other
purposes, or which are not optimal or appropriate for use by the volume, you can evacuate these.
To evacuate certain disks on which a volume is configured, use either of the following commands
to specify these:
# vxvoladm [-g diskgroup] [-b] evacuate disk volume \
!dmname ... [use_storage=rule[,...]] [attributes...]
# vxvoladm [-g diskgroup] [-b] evacuate disk volume \
evac_storage=rule[,...] [use_storage=rule[,...]] \
[attributes...]
The disk media names of the disks that are to be evacuated are specified as !dmname where
dmname is a disk media name. Alternatively, you can also use the storage specification attribute,
evac_storage, to specify rules for evacuating currently used storage. The -b option may be
specified to run the evacuation as a background task. ISP allocates suitable storage according the
autogrow policy of the storage pool, or you can use the storage specification attribute,
use_storage, to specify rules for allocating new storage.