topic Re: Bottleneck in Operating System - HP-UX

Bottleneck

Uday_S_Ankolekar — Mon, 09 Jul 2001 15:09:19 GMT

How can I find which disk has bottleneck..?
My IT/O gives this error. I tried with Glance. But I could not find which perticular disk/s give this bottleneck error. and how to resolve this.

I'm getting this error on a T and N box running HPUX 10.20 and 11.00 respectively. T is a Oracle Application server and N is Database server

Re: Bottleneck

Jim Turner — Mon, 09 Jul 2001 15:53:46 GMT

Uday,

If you've got Glance, this will be a lead pipe cinch. Just start Glance and hit "u" (no quotes) to go to the "IO By Disk" screen. I've attached a sample output from one of my machines.

All The Best,
Jim

Re: Bottleneck

Pedro Sousa — Mon, 09 Jul 2001 16:09:40 GMT

Hi Uday,
Jim gave you a good hint, but you can use another tool called 'sar' by issuing:
sar -d
where n specifies the number of intervals and t specifies the time of each interval in seconds.
for example:
sar -d 5 10
this will give you the disks activity in 10 intervals of 5 seconds (i.e. 50 seconds of activity).

good luck.

Re: Bottleneck

MANOJ SRIVASTAVA — Mon, 09 Jul 2001 16:53:31 GMT

Hi Uday

Do a sar -d 2 10 and pipe the output in a file , it will record averages for the devices adn give you the results.

Manoj Srivastava

Re: Bottleneck

Uday_S_Ankolekar — Mon, 09 Jul 2001 17:57:40 GMT

Hello,
I myself tried all the 'sar' options before I came to you. How can I find from sar -d about the disk bottleneck..?

Re: Bottleneck

MANOJ SRIVASTAVA — Mon, 09 Jul 2001 18:31:27 GMT

Hi Uday

So you want to intrepret the data from sar -d

, check for the high no. of averages in the fields %busy , avque ,avwait , these are the fields which would definatley give you the cluse , in case the period is small then run it for a long time.

Also could you download sarcheck from www.sarcheck.com , this owuld help you to incase of analysing sar out put .

You can also install glance . Or attach the output for sar -d 2 10 to this forum so that we can help you.

Manoj Srivastava