On 12/16/05, Chasecreek Systemhouse <chasecreek.systemhouse@xxxxxxxxx> wrote: > On 12/15/05, Al Sparks <data345@xxxxxxxxx> wrote: > > I'm running RHES 4. I installed sysstat 5.0.5-1 using up2date. > > However, when I run sar, it's showing all zeros regarding disk > > activity. Other gnome tools do show disk activity. > > > > Is there a problem out there with that tool not working with the 2.6 > > kernel? > > If your system is mostly idle then there may not be any sar activity > to report for disk processes. If sar is called without any arguments, it will try to read /var/log/sa/sarXX and /var/log/sa/saXX where XX is the current day of the month. You'll need to initialize these files yourself after installing sar (or allow the rpm provided cron entry to do it for you). In order to get sar output without these accounting files in place, you need to tell sar at what interval in seconds you want output, and how many interrations you want output for. Eg; [cbell@circe ~]$ sar 1 5 Linux 2.6.14-1.1644_FC4 (circe.inetdb.com) 12/16/2005 06:32:11 PM CPU %user %nice %system %iowait %idle 06:32:12 PM all 0.99 0.00 0.00 0.00 99.01 06:32:13 PM all 0.00 0.00 0.00 0.00 100.00 06:32:14 PM all 0.00 0.00 0.00 0.00 100.00 06:32:15 PM all 0.00 0.00 0.99 0.00 99.01 06:32:16 PM all 0.00 0.00 0.00 0.00 100.00 Average: all 0.20 0.00 0.20 0.00 99.60 [cbell@circe ~]$ Installing the sar package drops a file in /etc/cron.d called sysstat that collects performance data every 10 minutes and records it in the /var/log/sa accounting files. The link provided by Thomas Springer is a really good basic overview of sar, and how to initialize those accounting files: http://www.redhat.com/magazine/011sep05/features/tools/#sar The commands that initialize (and use) the accounting files are actually what's being run out of that crontab file that the sysstat package installs for you, so once you install it, you can wait 10 minutes or a day or whatever and get the information you're looking for from "sar without any arguments." To be honest, I've yet to determine what, exactly, the /etc/init.d/sysstat init script does that's also installed by the sysstat package. It seems to create a /var/log/sa/sa file that's never touched again. In looking at the file, it doesn't run any daemon, either. Anyway, best of luck! -- Chris "I trust the Democrats to take away my money, which I can afford. I trust the Republicans to take away my freedom, which I cannot."
