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RE: RMAN Performance Maladies

From: Herring Dave - dherri <>
Date: Mon, 12 Feb 2007 12:10:40 -0600
Message-ID: <>

Here's some average stats for our hot backups with 6 channels configured and filesperset at 6 as well, using Legato with RMAN:


----------- ------------------ ---------------- ------------------------
D                       502.35         2,790.66                    27.92
I                       156.44           280.40                     6.43
L                        31.79            84.80                    26.85

We have a full done weekly, incremental 6 days a week, and archive-only every day at 7am.

No tuning done but then again not a lot is available to tune.

HTH. Dave

David C. Herring, DBA | A c x i o m D e l i v e r y C e n t e r O r g a n i z a t i o n

630-944-4762 office | 630-430-5988 wireless | 630-944-4989 fax

> -----Original Message-----
> From:

> On Behalf Of Michael Fontana
> Sent: Monday, February 12, 2007 10:15 AM
> To:
> Subject: RMAN Performance Maladies
> We have just implemented RMAN against our largest Siebel
> (don't laugh - but it's less then 1/2 terrabyte).
> We did so because now that we have upgraded to Oracle 10gR2 (
> we can take advantage of flash recovery features and full backup
> compression similar to which we achived with our old backup product
> Sqlbacktrack). We customarily take full backups nightly, as per our
> SLA, and at this point, incrementals are not an option. However, the
> actual runtime to complete a full database backup with RMAN compared
> SqlBackTrack has gone from 30 minutes to over 4 1/2 hours!
> I have seen anecdotal reports of long runtimes for full RMAN backups
> this list, but I've seen an overwhelming number of guffaws from the
> elite and experienced poster indicating that this must be user error
> some other database performance problem that any competent DBA should
> easily be able to solve without posting to this list. However, even
> after opening an SR with Oracle support, who seems to believe our
> runtime is in the expected range, we still believe something can be
> to overcome the huge IO spike and slow performance we are witnessing
> during the backup, and we are not that experienced with RMAN from a
> performance and tuning perspective, and would appreciated anyone's
> insights or experiences.
> My question is - has anyone actually run RMAN against a large (> 200g)
> database right out of the box without tuning?
> Has anyone spent a great deal of time tuning?
> We are running 4 channels, have an 8 cpu Sunsparc solaris with 16g of
> memory, and have experimented with recommended parameter settings for
> maxsetsize and maxfilesperset without success. Any information or
> assistance or comment would be appreciated, thanks in advance!
> --

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Received on Mon Feb 12 2007 - 12:10:40 CST

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