Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

Note: mirror=mediatype is not supported.
Creating a RAID-5 volume
A RAID-5 volume requires space to be available on at least as many disks in the
disk group as the number of columns in the volume. Additional disks may be
required for any RAID-5 logs that are created.
Note: VxVM supports the creation of RAID-5 volumes in private disk groups, but
not in shareable disk groups in a cluster environment.
You can create RAID-5 volumes by using either the vxassist command
(recommended) or the vxmake command. Both approaches are described below.
A RAID-5 volume contains a RAID-5 data plex that consists of three or more
subdisks located on three or more physical disks. Only one RAID-5 data plex can
exist per volume. A RAID-5 volume can also contain one or more RAID-5 log plexes,
which are used to log information about data and parity being written to the
volume.
See “RAID-5 (striping with parity)” on page 44.
Warning: Do not create a RAID-5 volume with more than 8 columns because the
volume will be unrecoverable in the event of the failure of more than one disk.
To create a RAID-5 volume, use the following command:
# vxassist [-b] [-g diskgroup] make volume length layout=raid5 \
[ncol=number_of_columns] [stripewidth=size] [nlog=number] \
[loglen=log_length]
Specify the -b option if you want to make the volume immediately available for
use.
See “Initializing and starting a volume” on page 326.
For example, to create the RAID-5 volume volraid together with 2 RAID-5 logs
in the disk group, mydg, use the following command:
# vxassist -b -g mydg make volraid 10g layout=raid5 nlog=2
This creates a RAID-5 volume with the default stripe unit size on the default
number of disks. It also creates two RAID-5 logs rather than the default of one
log.
321Creating volumes
Creating a RAID-5 volume