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Date: Mon, 3 Dec 2007 16:21:28 -0800 (PST)
Subject: Re: Tuning RMAN backup and recovery
From: krish.hariharan@quasardb.com
To: don@seiler.us
Cc: krish.hariharan@quasardb.com, pythianbrinsmead@gmail.com,
        "Greg Rahn" <greg@structureddata.org>,
        "Robert Freeman" <robertgfreeman@yahoo.com>,
        "Oracle-L Freelists" <oracle-l@freelists.org>
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Reply-to: krish.hariharan@quasardb.com

Don,

Sorry, I did not realize that you had sent this to me and not to the
group. Two things. In your case I think you are constrained by speed and
you can try to overcome by using more channels to increase your
throughput.

The channel processes are not going to be writing all the time there are
going to be bottlenecks. Therefore having more channels may be ok to the
extent that you don't compete wiht yourself.

You should use the metrics associated with io such as service time and the
time it takes to execute your backup as a measure for how to design this.
As was discussed in this thread you are going to be constrained by the
theoretical maximum of the choice you make (raid 0+1 vs raid 5 for
example)

In your case however, the disk optimizations are not likely to help since
you are not io constrained.

Regards,
-Krish

> So if I have just the one /rman LUN, does it even make sense to have
> more than 1 channel, even if /rman is on its own spindles?  What about
> the fact that the LUN is made up multiple disks sliced and diced (e.g.
> a 3D+3P raid group)?
>
> --
> Don Seiler
> http://seilerwerks.wordpress.com
> ultimate: http://www.mufc.us
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>


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