VERITAS Volume Manager 3.5 Administrator's Guide (September 2002)

Chapter 12, Performance Monitoring and Tuning
Performance Monitoring
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where dest_disk is the disk to which you want to move the volume. It is not necessary to
specify a dest_disk. If youdo not specifya dest_disk, thevolume is movedto an available
disk with enough space to contain the volume.
For example, to move the volume from disk03 to disk04, use the following command:
# vxassist move archive !disk03 disk04
This command indicates that the volume is to be reorganized so that no part remains on
disk03.
Note The graphical userinterface (GUI) provides an easy way to movepieces of volumes
between disks and may be preferable to using the command line.
If twovolumes (other than the root volume)on the same disk are busy, movethem 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 canbe made instead.To converta volume, create a stripedplex as a mirror of
the volume and then remove the old plex. For example, the following commands stripe
the volume archive across disks disk02, disk03, and disk04, and then remove the
original plex archive-01:
# vxassist mirror archive layout=stripe disk02 disk03 disk04
# vxplex -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 disksappear to beexcessively busy (or haveparticularly long read or writetimes),
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.
Use I/O tracing (or subdisk statistics) to determine whether volumes have excessive
activity inparticular regions of thevolume. If the active regions canbe identified, split the
subdisks in the volume and move those regions to a less busy disk.