AIX Tip of the Week: New "sar" Flag for Disk Activity

Audience: Systems Administrators

Date: August 6, 2000

Starting with AIX 4.3.3, sar has a new -d flag that lists detailed disk activity. A sample of the "sar -d" output is below.

00:00:02     device    %busy    avque    r+w/s   blks/s   avwait   avserv
00:20:02     hdisk3      0      0.0        0        0      0.0      0.0
             hdisk0      0      0.0        0        1      0.0      0.0
             hdisk1      0      0.0        0        0      0.0      0.0
             hdisk2      0      0.0        0        0      0.0      0.0
             hdisk4      0      0.0        0        0      0.0      0.0
                cd0      0      0.0        0        0      0.0      0.0        

The sar command can be used to collect performance data over a period of time to determine peaks and trends. To facillitate data collection, AIX provides two shell scripts (/usr/lib/sa/sa1 and /usr/lib/sa/sa2). The scripts are normally run as a cron job from the "adm" id's. Sample stanzas are included (but commented out) in the /var/spool/cron/crontab/adm crontab file.

For more information see the sa1 documentation.