topic Re: Sar -d for tape devices in Operating System - HP-UX

Sar -d for tape devices

JHL_1 — Tue, 30 Oct 2001 19:23:43 GMT

I'm trying to run sar -d in order to check the performance of my tape devices (DLT 7000). While the man page for sar reports that I can use the -d option for block devices such as tape drives, I am not getting avserv/avwait values on any tape devices. This is true on any HP system I test this on. Any ideas on how to get "sar -d" data for tape drives?

Re: Sar -d for tape devices

Uday_S_Ankolekar — Tue, 30 Oct 2001 19:41:04 GMT

Hi,

sar -d will give you only for the active device

When you run sar probably your tape device was not at all active.

-USA..

Re: Sar -d for tape devices

A. Clay Stephenson — Tue, 30 Oct 2001 19:47:06 GMT

Hi John:

Sar -d only works for block devices. Under HP-UX the tape drives are character devices. Under some flavor of UNIX, there were both character and block devices associated with tape drives. In fact, you could even have a filesystem on a tape.

Re: Sar -d for tape devices

JHL_1 — Tue, 30 Oct 2001 19:48:54 GMT

I'm running the sar -d with the -f option which allows me to see values for the whole 24-hour period. I know the tape drives were active during this period but still do not see any values.

Re: Sar -d for tape devices

Sanjay_6 — Tue, 30 Oct 2001 20:30:37 GMT

Hi John,

Take a look at the thread below,

http://us-support.external.hp.com/cki/bin/doc.pl/sid=19a11661100c6eb7e1/screen=ckiDisplayDocument?docId=200000009872497

hope this helps.

thanks

Re: Sar -d for tape devices

harry d brown jr — Tue, 30 Oct 2001 21:13:06 GMT

John,

sar, vmstat, iostat are not able to catch everything because of process scheduling. If you don't already have glance, you can install a trial version. glance will allow you to "watch" the device as it performs.

live free or die
harry