Veritas Storage Foundation Intelligent Storage Provisioning 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

86 Administering application volumes
Changing the stripe unit size of volumes
Changing the stripe unit size of volumes
To change the stripe unit size of a striped or RAID-5 volume, use the following
command:
# vxassist [-g diskgroup ] [-b] setstwidth volume \
stripeunit= size [tmplen= length ] [ attributes ...]
If specified, the -b option changes the stripe width in the background.
Note: This operation creates a temporary 2-way mirror volume that requires at
least two disks, and therefore twice as much disk space as the size of the
temporary volume. The size of the temporary volume is based on the size of the
volume that is being changed. If required, you can use the
tmplen attribute to
specify the size of the temporary volume.
For example, the following command changes the stripe unit size of the volume
vol1 to 32KB:
# vxassist -g mydg -b setstwidth vol1 stripeunit=32k
Adding logs to a volume
To add logs to a volume, use the following command:
# vxassist [-g diskgroup ] [-b] addlog volume logtype= type \
[nlogs=
number ] [loglen=length] [ attributes ...]
The supported log types are 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.
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.