Re: RMAN - 11g Full backup Times

http://jaredstill.com/downloads/Making-RMAN-Perform.zip

Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist Oracle Blog: http://jkstill.blogspot.com Home Page: http://jaredstill.com

On Sat, Mar 19, 2011 at 11:05 AM, Jared Still <jkstill_at_gmail.com> wrote:

> On Thu, Mar 10, 2011 at 9:33 AM, Patty Vonick <patty.vonick_at_returnpath.net
> > wrote:
>
>>
>> Any estimates as to how long an RMAN incremental level-0 (full) backup
>> might take to run – say when backed-up to a local mount and/or to an NFS
>> mount? Right now, we’re allocating 8 channels.
>>
>>
> No way for me to estimate that, but perhaps I can help you do so.
>
> In 2008 I presented on RMAN performance at Hotsos.
>
> The presentation includes info about some tools that will
> help you determine how much you can push across the
> network.
>
> One simple method is to create a tablespace on the same
> destination for the backups. It's a fairly good determination
> of how fast it might go.
>
> I would not think allocating 8 channels in this situation would
> be ideal, unless you have a large disparity between how fast
> you can pull data from disk, and how fast you can write it to
> the backup destination.
>
> Ultimately there's only one way to know, and that is to test it.
>
>
>>
>>
>> Also – has anyone experienced a significant decrease in RMAN backup I/O
>> throughput after upgrading from 10g to 11g – resulting in backups taking
>> 2-3x longer than before the upgrade? If so, any suggestions?
>>
>>
> No, I have not experienced that myself.
>
> There are so many moving parts in an enterprise system, you just
> need to find where that bottleneck is.
>
> You might start with testing the write speed to the backup destination.
>
> What else changed during the upgrade?
>
> Network changes?
>
> Storage changes?
>
> Was the backup schedule changed so that now it runs during a different
> time?
>
> Have developers/operators/users pile on more batch jobs during the backup
> window?
> (I've seen this one triple backup times)
>
> HTH
>
> Jared Still
> Certifiable Oracle DBA and Part Time Perl Evangelist
> Oracle Blog: http://jkstill.blogspot.com
> Home Page: http://jaredstill.com
>
>
>

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