topic Re: IO testing and tuning in Operating System - HP-UX

IO testing and tuning

lawrenzo_1 — Thu, 03 Jan 2008 17:29:34 GMT

Hi all,

hope everyone had a good christmas and newyear .... I worked for most of it but will be getting lots of $$$$$ (happy days) ...

Let me get back to the question in hand:

I want to play around with system IO tuning and understand some of the parameters and the effects of changing. I have a couple crash and burn servers running hpux and AIX and I was hoping someone had a program or could point me to some method where I can increae the IO on the disks to 100% and create bottlenecks etc so I can determine different tuning methods.

does anyone have such a program?

many thanks

Chris

Re: IO testing and tuning

Eric SAUBIGNAC — Thu, 03 Jan 2008 17:38:27 GMT

Bonsoir Chris,

Maybe IOZONE is your answer. Take a look at http://www.iozone.org/

Regards

Eric

Re: IO testing and tuning

Hasan Atasoy — Thu, 03 Jan 2008 17:40:19 GMT

hi chris ;

a) Bonnie+

http://www.coker.com.au/bonnie++/

b) IOzone

http://www.iozone.org/

c) IOstone

http://www.acnc.com/benchmarks/iostone.zip

d) IObench

http://www.acnc.com/benchmarks/iobench.tar.Z

e) Bonnie

http://www.acnc.com/benchmarks/bonnie.tar.gz

f) nbench

http://www.tux.org/~mayer/linux/bmark.html

from the url

http://forums12.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1199381950289+28353475&threadId=1187415

Hasan

Re: IO testing and tuning

James R. Ferguson — Thu, 03 Jan 2008 17:40:59 GMT

Hi Chris (and Happy New Year to you too):

Creating I/O on disks can be as simple as using 'dd'. For example, to read a disk in block sizes of 1024 characters having skipped 2048 blocks before starting and quit after reading 100 blocks, do:

# dd if=/dev/rdsk/c0t6d0 of=/dev/null bs=1024 iseek=2048 count=100

Notice the use of the raw device file. This means that you don't involve the Unix buffer cache in your reads.

As for writing, you could use '/dev/zero' as your input ('if') file, BUT MAKE VERY SURE that your output disk is not one with any viable data, since you will be smearing zeros all over it!

Clearly, a script with a number of 'dd' processes can be quickly hacked together to build up so I/O. As always, see the manpages for 'dd(1)' for more information.

Regards!

...JRF...

Re: IO testing and tuning

Jannik — Thu, 03 Jan 2008 21:27:47 GMT

I have been playing round with IO test as well. I have used IOZONE, which is better than dd because you can create a lot o threads. And the measuring is build in.

Remember to play around with Block Size and the filesystem cache (dbc_min_pct and dbc_max_pct in 11i until v3 then it is fs something).

Re: IO testing and tuning

lawrenzo_1 — Mon, 07 Jan 2008 13:11:08 GMT

Thats great,

I have been running the dd command to test times and activity so thanks James.

and also thanks for the suggested programs.

Chris.