VERITAS Volume Manager 3.1 Administrator's Guide

Performance Monitoring

Chapter 9400

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 user interface provides an easy way to move pieces of

volumes between disks and may be preferable to using the

command-line.

If there are two busy volumes (other than the root volume), move them

so that each is on a different disk.

If there is one volume that 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 to striping,

create a striped plex of the volume and then remove the old plex. For

example, to stripe the volume archive across disks disk02, disk03, and

disk04, use the following command:

# 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 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.

Use I/O tracing (or subdisk statistics) to determine whether volumes

have excessive activity in particular regions of the volume. If the active

regions can be identiﬁed, split the subdisks in the volume and move

those regions to a less busy disk.