Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

249Creating volumes
Creating a volume using vxmake
The tag names site, udid and vdid are reserved and should not be used. To avoid
possible clashes with future product features, it is recommended that tag names do not
start with any of the following strings: asl, be, isp, nbu, sf, symc or vx.
See “Setting tags on volumes” on page 280.
Creating a volume using vxmake
As an alternative to using vxassist, you can create a volume using the vxmake
command to arrange existing subdisks into plexes, and then to form these plexes into a
volume. Subdisks can be created using the method described in “Creating subdisks” on
page 207. The example given in this section is to create a RAID-5 volume using
vxmake.
Creating a RAID-5 plex for a RAID-5 volume is similar to creating striped plexes, except
that the layout attribute is set to raid5. Subdisks can be implicitly associated in the
same way as with striped plexes. For example, to create a four-column RAID-5 plex with
a stripe unit size of 32 sectors, use the following command:
# vxmake -g mydg plex raidplex layout=raid5 stwidth=32 \
sd=mydg00-01,mydg01-00,mydg02-00,mydg03-00
Note that because four subdisks are specified, but the number of columns is not specified,
the
vxmake command assumes a four-column RAID-5 plex and places one subdisk in
each column. Striped plexes are created using the same method except that the layout is
specified as stripe. If the subdisks are to be created and added later, use the following
command to create the plex:
# vxmake -g mydg plex raidplex layout=raid5 ncolumn=4 stwidth=32
Note: If no subdisks are specified, the ncolumn attribute must be specified. Subdisks can
be added to the plex later using the
vxsd assoc command (see “Associating subdisks
with plexes” on page 210).
If each column in a RAID-5 plex is to be created from multiple subdisks which may span
several physical disks, you can specify to which column each subdisk should be added.
For example, to create a three-column RAID-5 plex using six subdisks, use the following
form of the
vxmake command:
# vxmake -g mydg plex raidplex layout=raid5 stwidth=32 \
sd=mydg00-00:0,mydg01-00:1,mydg02-00:2,mydg03-00:0, \
mydg04-00:1,mydg05-00:2
This command stacks subdisks mydg00-00 and mydg03-00 consecutively in column
0, subdisks mydg01-00 and mydg04-00 consecutively in column 1, and subdisks
mydg02-00 and mydg05-00 in column 2. Offsets can also be specified to create sparse
RAID-5 plexes, as for striped plexes.