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

Chapter 12, Performance Monitoring and Tuning

Performance Monitoring

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The following is an example of output produced using the vxstat command:

OPERATIONS BLOCKS AVG TIME(ms)

TYP NAME READ WRITE READ WRITE READ WRITE

vol blop 0 0 0 0 0.0 0.0

vol foobarvol 0 0 0 0 0.0 0.0

vol rootvol 73017 181735 718528 1114227 26.8 27.9

vol swapvol 13197 20252 105569 162009 25.8 397.0

vol testvol 0 0 0 0 0.0 0.0

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 touse resourcesmost effectively. Thefollowing sectionsprovidean overview

of how you can use this data.

Using I/O Statistics

Examination ofthe I/O statistics can suggesthow to reconﬁgure your system.You should

examine two primary statistics: volume I/O activity and disk I/O activity.

Beforeobtaining statistics, reset the countersfor all existingstatistics 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.