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

279Administering volumes
Setting tags on volumes
If a volume is active and its length is being reduced, the operation must be forced using the
-o force option to
vxvol. This prevents accidental removal of space from applications
using the volume.
The length of logs can also be changed using the following command:
# vxvol [-g diskgroup] set loglen=length log_volume
Note: Sparse log plexes are not valid. They must map the entire length of the log. If
increasing the log length would make any of the logs invalid, the operation is not allowed.
Also, if the volume is not active and is dirty (for example, if it has not been shut down
cleanly), the log length cannot be changed. This avoids the loss of any of the log contents
(if the log length is decreased), or the introduction of random data into the logs (if the log
length is being increased).
Setting tags on volumes
Volume tags are used to implement the Dynamic Storage Tiering feature of the Storage
Foundation software. For more information about this feature, see the Veritas File System
Administrator’s Guide.
You can use the following forms of the
vxassist command to set a named tag and
optional tag value on a volume, to replace a tag, and to remove a tag from a volume:
# vxassist [-g diskgroup] settag volume tagname[=tagvalue]
# vxassist [-g diskgroup] replacetag volume oldtag newtag
# vxassist [-g diskgroup] removetag volume tagname
To list the tags that are associated with a volume, use this command:
# vxassist [-g diskgroup] listtag volume
To list the volumes that have a specified tag name, use this command:
# vxassist [-g diskgroup] list tag=tagname volume
Tag names and tag values are case-sensitive character strings of up to 256 characters. Tag
names can consist of letters (A through Z and a through z), numbers (0 through 9), dashes
(-), underscores (_) or periods (.) from the ASCII character set. A tag name must start with
either a letter or an underscore. Tag values can consist of any character from the ASCII
character set with a decimal value from 32 through 127. If a tag value includes any spaces,
quote the specification to protect it from the shell, as shown here:
# vxassist -g mydg settag myvol "dbvol=table space 1"
Dotted tag hierarchies are understood by the list operation. For example, the listing for
tag=a.b includes all volumes that have tag names that start with a.b.
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.