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

248 Creating volumes
Creating tagged volumes
plexes for each RAID-5 volume protects against the loss of logging information due to the
failure of a single disk.
If you use ordered allocation when creating a RAID-5 volume on specified storage, you
must use the
logdisk attribute to specify on which disks the RAID-5 log plexes should
be created. Use the following form of the
vxassist command to specify the disks from
which space for the logs is to be allocated:
# vxassist [-b] [-g diskgroup] -o ordered make volume length \
layout=raid5 [ncol=number_columns] [nlog=number] \
[loglen=log_length] logdisk=disk[,disk,...] storage_attributes
For example, the following command creates a 3-column RAID-5 volume with the default
stripe unit size on disks mydg04, mydg05 and mydg06. It also creates two RAID-5 logs
on disks mydg07 and mydg08.
# vxassist -b -g mydg -o ordered make volraid 10g layout=raid5 \
ncol=3 nlog=2 logdisk=mydg07,mydg08 mydg04 mydg05 mydg06
Note: The number of logs must equal the number of disks specified to logdisk.
For more information about ordered allocation, see “Specifying ordered allocation of
storage to volumes” on page 236 and the vxassist(1M) manual page.
If you need to add more logs to a RAID-5 volume at a later date, follow the procedure
described in “Adding a RAID-5 log” on page 275.
Creating tagged 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
tag attribute with the vxassist make command to set a named tag and
optional tag value on a volume, for example:
# vxassist -b -g mydg make volmir 5g layout=mirror tag=mirvol=5g
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,
use the
vxassist settag command to set the tag on the newly created volume.
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.