RMAN Peformance and how to optimise

From: <John.Hallas_at_gb.vodafone.co.uk>
Date: Tue, 17 Feb 2004 19:42:30 -0000
Message-ID: <1C6E45ADB2EC324F9553E468ABFE0F63E0403D@UKWMXM04>

We are seeing poor performance when recovering a full database (65 = datafiles) , during backup revovery (testing I hasten to add so not job = or life threatening)

Oracle 9202 Legato Networker 7 (I think) filesperset 1 2 tape drives 8 = channels

What appears to be the problem is that the order that the backup was = taken (full) does not co-incide with the order that the files are being = recovered (using RMAN logs to tell the order)

>From NW we are seeing 1 channel reading from tape and laying down the =
file to disk and 7 channels idle.
We suspect that they are waiting on the same tape but for a different = part of the tape.
Ideally what we want is a means of RMAN recovering the datafiles in the = order they are on the tape.

I have seen a note on Metalink suggesting that either 1 or 2 channels is = best per available tape drive.

We have to strike a balance betweeen the backup time and the recovery = time with neither taking extremes.

Has anybody done any work in this area that could offer some useful = insights

Thanks

John

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Received on Tue Feb 17 2004 - 13:42:30 CST