topic Re: monitor I/O with sar on dl360 in Operating System - Linux

monitor I/O with sar on dl360

Martin_146 — Tue, 15 Nov 2005 06:20:59 GMT

Hello!

I wonder why sar won't output the I/O activity when i run 'sar -b' on my ProLiant DL360 G4 server with RedHat Enterprise Linux 3, kernel 2.4.21-20.ELsmp. I have made the raid with the external Smart Array card. The devices I want to monitor is /dev/cciss/c0d0p*.

To monitor the cpu with the sar command is no problem, but the disk won't work.

Proliant Support pack 7.20 is installed.

Thanks in advance.
//Martin

Re: monitor I/O with sar on dl360

Steven E. Protter — Tue, 15 Nov 2005 07:40:09 GMT

Please show us the command you are using and the system response.

SEP

Re: monitor I/O with sar on dl360

Ivan Ferreira — Tue, 15 Nov 2005 08:17:21 GMT

If sar does not work, you can use iostat.

Re: monitor I/O with sar on dl360

Martin_146 — Tue, 15 Nov 2005 08:28:08 GMT

Sure here is an example that should give some numbers othern than zero.

$ dd if=/dev/zero of=BIGFILE bs=1024 count=1000000

[1]+ Stopped dd if=/dev/zero of=BIGFILE bs=1024 count=1000000
$ bg
[1]+ dd if=/dev/zero of=BIGFILE bs=1024 count=1000000 &
$ sar -b 2 2000
Linux 2.4.21-20.ELsmp (hostname) 11/15/2005

02:15:24 PM tps rtps wtps bread/s bwrtn/s
02:15:26 PM 0.00 0.00 0.00 0.00 0.00
02:15:28 PM 0.00 0.00 0.00 0.00 0.00
02:15:30 PM 0.00 0.00 0.00 0.00 0.00
02:15:32 PM 0.00 0.00 0.00 0.00 0.00
02:15:34 PM 0.00 0.00 0.00 0.00 0.00
02:15:36 PM 0.00 0.00 0.00 0.00 0.00
02:15:38 PM 0.00 0.00 0.00 0.00 0.00
02:15:40 PM 0.00 0.00 0.00 0.00 0.00
1000000+0 records in
1000000+0 records out
02:15:42 PM 0.00 0.00 0.00 0.00 0.00
02:15:44 PM 0.00 0.00 0.00 0.00 0.00

[1]+ Done dd if=/dev/zero of=BIGFILE bs=1024 count=1000000

First I run the 'dd' command to generate some i/o then I put it in the background and then start 'sar -b' to watch the activity. When I run these commands on another server (not a dl360 with raid) it works fine.

Thanks!
//Martin

Re: monitor I/O with sar on dl360

Martin_146 — Tue, 15 Nov 2005 10:31:56 GMT

Thanks for the tip Ivan.
But I'm monitoring several servers with a script that use sar. 3 of them are dl360 G4 and the rest of them are "unknown" servers. It would be easier to get sar to work on the HP servers than changing the script.

Thanks
Martin