VERITAS Volume Manager 4.1 Administrator's Guide

Performance Monitoring and Tuning
Performance Monitoring
Chapter 12402
OPERATIONS BLOCKS AVG TIME(ms)
TYP NAME READ WRITE READ WRITE READ WRITE
vol blop 00000.00.0
vol foobarvol 00000.00.0
vol rootvol 73017 181735 718528 1114227 26.8 27.9
vol swapvol 13197 20252 105569 162009 25.8 397.0
vol testvol 00000.00.0
Additional volume statistics are available for RAID-5 configurations.
For detailed information about how to use vxstat, refer to the vxstat
(1M) manual page.
Using Performance Data
When you have gathered performance data, you can use it to determine
how to configure your system to use resources most effectively. The
following sections provide an overview of how you can use this data.
Using I/O Statistics
Examination of the I/O statistics can suggest how to reconfigure your
system. You should examine two primary statistics: volume I/O activity
and disk I/O activity.
Before obtaining statistics, reset the counters for all existing statistics
using the vxstat -r command. This eliminates any differences between
volumes or disks due to volumes being created, and also removes
statistics from boot time (which are not usually of interest).
After resetting the counters, allow the system to run during typical
system activity. Run the application or workload of interest on the
system to measure its effect. When monitoring a system that is used for
multiple purposes, try not to exercise any one application more than
usual. When monitoring a time-sharing system with many users, let
statistics accumulate for several hours during the normal working day.
To display volume statistics, enter the vxstat command with no
arguments. The following is a typical display of volume statistics:
OPERATIONS BLOCKS AVG TIME(ms)
TYP NAME READ WRITE READ WRITE READ WRITE
vol archive 865 807 5722 3809 32.5 24.0
vol home 2980 5287 6504 10550 37.7 221.1
vol local 49477 49230 507892 204975 28.5 33.5
vol rootvol 102906 342664 1085520 1962946 28.1 25.6