Creating and administering subdisks 219

Associating subdisks with plexes

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 [-gdiskgroup] assoc plex subdisk1 [subdisk2 subdisk3 ...]

For example, to associate subdisks named mydg02-01, mydg02-00, and mydg02-02with 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 -loption is specified with the command. The -loption associates subdisks at a specific offset within the plex.

The -loption 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 [-gdiskgroup] -loffset assoc sparse_plex exact_size_subdisk

For example, the following command would insert the subdisk, mydg15-01, in the plex, vol10-01, starting at an offset of 4096 blocks:

#vxsd -g mydg -l 4096b assoc vol10-01 mydg15-01

Note: The subdisk must be exactly the right size. VxVM does not allow the space defined for two subdisks to overlap within a plex.

For striped or RAID-5 plexes, use the following command to specify a column number and column offset for the subdisk to be added:

# vxsd [-gdiskgroup] -lcolumn_#/offset assoc plex subdisk ...

If only one number is specified with the -loption for striped plexes, the number is interpreted as a column number and the subdisk is associated at the end of the column.

For example, the following command would add the subdisk, mydg11-01, to the end of column 1 of the plex, vol02-01:

# vxsd -g mydg -l 1 assoc vol02-01 mydg11-01

Alternatively, to add M subdisks at the end of each of the or RAID-5 volume, you can use the following form of the

N columns in a striped vxsd command:
#vxsd [-g diskgroup] assoc plex subdisk1:0 ... subdiskM:N-1

The following example shows how to append three subdisk to the ends of the three columns in a striped plex, vol-01, in the disk group, mydg:

#vxsd -g mydg assoc vol01-01 mydg10-01:0 mydg11-01:1 \ mydg12-01:2

If a subdisk is filling a “hole” in the plex (that is, some portion of the volume logical address space is mapped by the subdisk), the subdisk is considered stale.