VERITAS Volume Manager 3.5 User's Guide - VERITAS Enterprise Administrator (September 2004)

Getting Started with VxVM VEA
Load Balancing
Chapter 2 43
Load Balancing
If disk activities are heavily concentrated on one or a small number of
disks in the storage subsystem, it may create bottlenecks. You can use
the “Moving a Subdisk” on page 148 and possibly the “Splitting a
Subdisk” on page 150 features to spread out disk accesses more evenly
across all the disks to balance the load.
If a disk has High or Critical I/O activity (shown by a red or yellow pie
symbol), you may consider moving one or more of its subdisks to another
disk that shows below average I/O activity (shown by a blue pie symbol).
The idea is to move just enough activity to achieve balance. A careful
study of the statistics for the disk with Critical activity may identify the
best subdisks to move. You should move subdisks only when a disk has
High or Critical I/O activity over a prolonged period of time and
performance is affected. Moving a subdisk to another disk has an effect
on I/O as well, but it should be compensated for by the other disk having
much lower I/O activity. You would need to look at the statistics after the
subdisk move to see whether the move was effective in balancing the
load.