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

210 Creating and administering subdisks
Associating subdisks with plexes
For example, to join the contiguous subdisks mydg03-02, mydg03-03, mydg03-04
and mydg03-05 as subdisk mydg03-02 in the disk group, mydg, use the following
command:
# vxsd -g mydg join mydg03-02 mydg03-03 mydg03-04 mydg03-05 \
mydg03-02
Associating subdisks with plexes
Associating a subdisk with a plex places the amount of disk space defined by the subdisk
at a specific offset within the plex. The entire area that the subdisk fills must not be
occupied by any portion of another subdisk. There are several ways that subdisks can be
associated with plexes, depending on the overall state of the configuration.
If you have already created all the subdisks needed for a particular plex, to associate
subdisks at plex creation, use the following command:
# vxmake [-g diskgroup] plex plex sd=subdisk,...
For example, to create the plex home-1 and associate subdisks mydg02-01, mydg02-
00, and mydg02-02 with plex home-1, all in the disk group, mydg, use the following
command:
# vxmake -g mydg plex home-1 sd=mydg02-01,mydg02-00,mydg02-02
Subdisks are associated in order starting at offset 0. If you use this type of command, you
do not have to specify the multiple commands needed to create the plex and then associate
each of the subdisks with that plex. In this example, the subdisks are associated to the plex
in the order they are listed (after sd=). The disk space defined as mydg02-01 is first,
mydg02-00 is second, and mydg02-02 is third. This method of associating subdisks is
convenient during initial configuration.
Subdisks can also be associated with a plex that already exists. To associate one or more
subdisks with an existing plex, use the following command:
# vxsd [-g diskgroup] assoc plex subdisk1 [subdisk2 subdisk3 ...]
For example, to associate subdisks named mydg02-01, mydg02-00, and mydg02-02
with a plex named home-1, use the following command:
# vxsd -g mydg assoc home-1 mydg02-01 mydg02-00 mydg02-01
If the plex is not empty, the new subdisks are added after any subdisks that are already
associated with the plex, unless the -l option is specified with the command. The -l
option associates subdisks at a specific offset within the plex.
The -l option is required if you previously created a sparse plex (that is, a plex with
portions of its address space that do not map to subdisks) for a particular volume, and
subsequently want to make the plex complete. To complete the plex, create a subdisk of a
size that fits the hole in the sparse plex exactly. Then, associate the subdisk with the plex
by specifying the offset of the beginning of the hole in the plex, using the following
command:
# vxsd [-g diskgroup] -l offset assoc sparse_plex exact_size_subdisk