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

458 Performance monitoring and tuning
Performance monitoring
Note: Your system may use device names that differ from these examples. For more
information on device names, see “Administering disks” on page 77.
The subdisks line (beginning sd) indicates that the volume archive is on disk mydg03.
To move the volume off mydg03, use the following command:
# vxassist -g mydg move archive !mydg03 dest_disk
Here dest_disk is the destination disk to which you want to move the volume. It is not
necessary to specify a destination disk. If you do not specify a destination disk, the volume
is moved to an available disk with enough space to contain the volume.
For example, to move a volume from disk mydg03 to disk mydg04, in the disk group,
mydg, use the following command:
# vxassist -g mydg move archive !mydg03 mydg04
This command indicates that the volume is to be reorganized so that no part of it remains
on mydg03.
Note: The Veritas Enterprise Administrator (VEA) has a graphical user interface (GUI),
which provides an easier way to move pieces of volumes between disks. You may find
that approach preferable to using the command line.
If two volumes (other than the root volume) on the same disk are busy, move them so that
each is on a different disk.
If one volume is particularly busy (especially if it has unusually large average read or
write times), stripe the volume (or split the volume into multiple pieces, with each piece
on a different disk). If done online, converting a volume to use striping requires sufficient
free space to store an extra copy of the volume. If sufficient free space is not available, a
backup copy can be made instead. To convert a volume, create a striped plex as a mirror of
the volume and then remove the old plex. For example, the following commands stripe the
volume archive across disks mydg02, mydg03, and mydg04 in the disk group,
mydg, and then remove the original plex archive-01:
# vxassist -g mydg mirror archive layout=stripe mydg02 mydg03 \
mydg04
# vxplex -g mydg -o rm dis archive-01
After reorganizing any particularly busy volumes, check the disk statistics. If some
volumes have been reorganized, clear statistics first and then accumulate statistics for a
reasonable period of time.
If some disks appear to be excessively busy (or have particularly long read or write times),
you may want to reconfigure some volumes. If there are two relatively busy volumes on a
disk, move them closer together to reduce seek times on the disk. If there are too many
relatively busy volumes on one disk, move them to a disk that is less busy.