Re: performance of redo with CIO option on AIX JFS2 filesystem.

Hi,

any idea what version of Oracle that you are using :-)

thanks for the info...

well, there is a lot of debate on 'log file sync' and 'log file parallel write' and there is timing bug too. Look at BUG: 2669566.

look at http://www.jlcomp.demon.co.uk/log_file_writes.html

also, what was your setting for disk_async_io, filesystemio_options and _lgwr_async_io?

did you modify any of these?

thanks

anand

On 14/02/06, The Human Fly <sjaffarhussain_at_gmail.com> wrote:
>
> Hello list,
>
> Today we have a light smile on our face because we were struggling
> with log file sync event on one of our business critical database. We
> opened a TAR and implemented everything they have suggested.
> Yesterday, we made litte changes, like, created a new mountpoint
> enabling CIO (concurrent I/O) on AIX 5.3 using JFS2 filesystem, and
> move our redo groups to this new mount point also increased the size
> of redo groups from 512M to 1gb.
> When we look at the log file sysn event in the statspack, it was just
> vanished. Earlier, we used to get 40% as log file synce in the top
> timed events and now it is just 3%. Its really a drastic change in the
> wait event.
> Now, I am planning to do the same for our datafiles, i.e. enabling cio
> and moving the tablespace to new moutn point. Redo has only inserts,
> but, for tables, we have read and write, does this can improve the
> throughput? Will there be any performance gain? Does anyone using this
> kind of option with JFS2 filesystem?
>
> Thanks for your time.
>
> --
> Best Regards,
> Syed Jaffar Hussain
> 8i,9i & 10g, OCP DBA
> Banque Saudi Fransi,
> Saudi Arabia
> http://jaffardba.blogspot.com/
>
> ----------------------------------------------------------------------------------
> "Winners don't do different things. They do things differently."
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

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