The sysstat
service which runs the sa
binaries is not collecting disk statistics in /var/log/sa
files. This is turned off by default to prevent the logs from growing large on systems with hundreds or thousands of block devices.
When you run sar
to report disk statistics, the Requested activities not available in file message is telling you that sa
hasn't been collecting disk statistics, so sar
can't display anything.
You can add config parameters with the SADC_OPTIONS
value in /etc/sysconfig/sysstat
The ability to do this was added in Bug 598794 so you'll need to be running sysstat-7.0.2-11.el5
or later.
Edit your /etc/sysconfig/sysstat
file to include a line like:
SADC_OPTIONS="-d"
then service sysstat restart
Give it some time for data to collect (at least 20 minutes), then sar -d
should work.