| RMAN backup performance [message #499695] |
Tue, 15 March 2011 14:14  |
John Watson
Messages: 8960
Registered: January 2010
Location: Global Village
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Senior Member |
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This database is about 175G. A full backup to disc usually takes about 4 hours (the backup sets are about 150G) but is very variable: from 1 hour to 9 hours. Restore and recover to a different machine is taking about 12 hours, consistently. This is standard edition, so no parallelism. The hardware is Sun V490 4 CPUs 64G RAM, and EMC Clariion storage, fibre channel attached. I really don't know a lot about the hardware. I've had a look at the wait events and v$session_longops while rman is running, nothing looks odd.
What I need is some idea of whether these timings seem sensible. I think that the hardware should be able to do this much faster: 175G isn't a lot of data. But before I start discussing this with the sys admins, I'ld really like some comparison figures from other sites. Does anyone have any figures they can share?
Thanks for any reply.
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| Re: RMAN backup performance [message #499979 is a reply to message #499695] |
Thu, 17 March 2011 01:17  |
hkchital
Messages: 128
Registered: September 2008
Location: Singapore
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Senior Member |
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Are you using multiple Channels, Automatic Parallelism ?
The datafiles are distributed across the channels. It so happens that on occassion a Channel gets a set of datafiles that add up to a very small size while another Channel that gets a set of datafiles that add up to a very large size. This is so if your database has files of very different sizes (some of 500MB to 2GB, many of 32GB). Check how the datafiles are distributed across the backupsets in each day's run.
Another factor is Archivelogs. If your backup includes Archivelogs, is the total volume of Archivelogs (number and size) approximately the same each day or does it vary significantly ?
Hemant K Chitale
[Updated on: Thu, 17 March 2011 02:10] by Moderator Report message to a moderator |
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