topic Re: How to get tape drive performance stats in Operating System - Linux

How to get tape drive performance stats

Victor Semaska_3 — Sat, 14 Oct 2006 09:50:14 GMT

Greetings,

OS: Linux 2.4.21-37.ELsmp
sar: sysstat version 5.0.5
Tape Drives: 4-LTO2s in MSL6060

I'm fairly new to Linux. I'm trying to get performance stats on the tape drives in the server (/dev/nst0 thru /dev/nst3). I've downloaded sar from RedHat's web-site and install it. I can't find any way in sar or some other utility to report on tape drive performance stats. Does anyone know how this can be done?

Thanks,
Vic

Re: How to get tape drive performance stats

Steven E. Protter — Sat, 14 Oct 2006 13:38:32 GMT

Shalom Vic,

From the OS perspective he tape drive is really just another disk.

sar -d should be able to collect informaiton on it.

SEP

Re: How to get tape drive performance stats

Victor Semaska_3 — Sat, 14 Oct 2006 18:19:20 GMT

Thanks Steve but the tape drives don't show up when I use 'sar -d'. Maybe it has something to do with the fact that the major id for the disks is 8 and for the tapes it's 9.

Vic

Re: How to get tape drive performance stats

Ivan Ferreira — Sat, 14 Oct 2006 22:40:08 GMT

Tape statistics cannot be obtained with the sar or any other command. The only Unix OS that allows tape statistics is Tru64 Unix through the "collect" utility.

sar "Reports activity for each block device with the exception of tape drives."

To test performance, you should use the "time" command to identify the time that took to store a certain ammount of data. The time and dd command normally are used to test performance, for example:

time dd if=/dev/zero of=/dev/st0 bs=1024k

If you MSL6060 is fibre channel attached, you can check the sanswitch port statistics.

Re: How to get tape drive performance stats

Ivan Ferreira — Sat, 14 Oct 2006 22:42:27 GMT

LTT is another interesting tool :

http://h20000.www2.hp.com/bizsupport/TechSupport/DriverDownload.jsp?pnameOID=406731&locale=en_US&taskId=135&prodSeriesId=406729&prodTypeId=12169

Re: How to get tape drive performance stats

Victor Semaska_3 — Sun, 15 Oct 2006 08:13:14 GMT

Ivan,

Thanks for the info. The sar manpage that I have makes no mention of tapes not being supported so that's why I was trying.

We're using Legato Networker (7.2.2) and I want to monitor tape performace during backups to see if the tapes are running in streaming mode. The Legato nwadmin utility shows tape performance but I assume that it's using internal counters.

The MSL6060 is attached directly to the server via SCSI ports so I can't use SAN statistics.

It sounds like the LTT utility wouldn't meet my needs either.

I guess the thing to do is time how long the nightly backups take, figure out how much data was written to tape, and do the math to determine the approximate MBs/sec transfer rate.

Thanks again,
Vic

Re: How to get tape drive performance stats

Neha Joshi — Tue, 07 Nov 2006 23:27:02 GMT

Hi Victor, Now HP-UX 11.31 have also this newly inroduced feature of displaying the TAPE Statistics.We can use sar with -t option. As also the man page says " -t Report activity for each tape device."