Re: Measuring the impact of Redo Log change

From: Syed Jaffar Hussain <>
Date: Tue, 9 Sep 2008 10:32:27 +0300
Message-ID: <>

We have seen significant improvements when we enable CIO option of the JFS2 filesystem where redo logs resides.If you are on JFS2 filesystem, I would recommend you to have a try with CIO option enable on this filesystem (where redo logs resides).



On Tue, Sep 9, 2008 at 7:32 AM, Deepak Sharma <>wrote:

> We recently (today) moved the redo logs from RAID5 to RAID1+0.
> The obvious reason of doing this is to make things better in terms of
> performance, as RAID1+0 is better suited for read/writes. Someone pls
> correct me if that's not true.
> What are different ways to measure the impact of this change?
> The platform is AIX, DB is and DB size is 55TB, and 2TB redo is
> generated each day. There are plans underway to reduce the redo generation
> using direct path etc. (so let's not get diverted by that).
> We can try measuring the wait event stats using AWR, session stats etc.,
> but what exactly to look for? 'log file switch completion', 'log file
> sync', are some things that come to mind - what else?
> Thanks,
> Deepak

Best Regards,

Syed Jaffar Hussain
Oracle ACE
8i,9i & 10g OCP DBA
RAC Certified Expert

Official Oracle RAC SIG Representative for Saudi Arabian region (
"Winners don't do different things. They do things differently."

Received on Tue Sep 09 2008 - 02:32:27 CDT

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