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Sar -d for tape devices

JHL_1
Frequent Advisor

Sar -d for tape devices

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?
5 REPLIES
Uday_S_Ankolekar
Honored Contributor

Re: Sar -d for tape devices

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..
Good Luck..
A. Clay Stephenson
Acclaimed Contributor

Re: Sar -d for tape devices

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.

If it ain't broke, I can fix that.
JHL_1
Frequent Advisor

Re: Sar -d for tape devices

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.
Sanjay_6
Honored Contributor

Re: Sar -d for tape devices

harry d brown jr
Honored Contributor

Re: Sar -d for tape devices

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
Live Free or Die