topic Re: Reads and Writes Methods in Operating System - HP-UX

Reads and Writes Methods

Slayer — Tue, 09 Aug 2005 02:20:09 GMT

Hello All,

HP-UX 11i

I would like to know if someone have a good method to for better high-speed "reads and writes to disk".
We are going to use a directory which has a big size in order to do this test.

TIA

Slayer

Re: Reads and Writes Methods

Mahesh Kumar Malik — Tue, 09 Aug 2005 03:05:17 GMT

Hi Slayer

Enable Asynchronous I/O - By default, HP-UX uses synchronous disk I/O, when writing file system "meta structures" (super block, directory blocks, inodes, etc.) to disk. This means that any file system activity of this type must complete writing to the disk before the program is allowed to continue; the process does not regain control until completion of the physical I/O. When HP-UX writes to disk asynchronously, I/O is scheduled at some later time and the process regains control immediately, without waiting.

Asynchronous writing of the file system meta structures is enabled by setting the value of the kernel parameter fs_async to 1

Regards
Mahesh

Re: Reads and Writes Methods

morganelan — Tue, 09 Aug 2005 03:09:45 GMT

Hi,
Please see this:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=886166

Re: Reads and Writes Methods

Slayer — Tue, 09 Aug 2005 03:11:06 GMT

Hey Mahesh,

Thanks a lot for the answer,

But do know any tool that can monitoring this activity ?

Best Regards,

Bruno

Re: Reads and Writes Methods

Muthukumar_5 — Tue, 09 Aug 2005 03:20:39 GMT

You can get read from disk and write to disk as,

# sar -b 1 5

hth.