Home » RDBMS Server » Backup & Recovery » RMAN backup performance (11.1.0.7 SE, Solaris)
RMAN backup performance [message #499695] Tue, 15 March 2011 14:14 Go to next message
John Watson
Messages: 4864
Registered: January 2010
Location: Global Village
Senior Member
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.
Re: RMAN backup performance [message #499701 is a reply to message #499695] Tue, 15 March 2011 14:52 Go to previous messageGo to next message
Michel Cadot
Messages: 60016
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
First check your io subsystem creating a say 50GB file:

dd if=/dev/zero of=<your file> bs=<your block size>


This will give you the maximum rate to create a 50G file.
Do it several times as time will depend on your Clarion use, above all if it is shared between several servers.

Then check concurrent CPU usage as RMAN much needs it. You can use "top" to follow it.
You can also have a "vmstat" session to check paging and swaping during the backup (and restore).

Regards
Michel
Re: RMAN backup performance [message #499702 is a reply to message #499695] Tue, 15 March 2011 14:58 Go to previous messageGo to next message
Mahesh Rajendran
Messages: 10630
Registered: March 2002
Location: oracleDocoVille
Senior Member
Account Moderator
It could really vary depending on the hardware.
For me,
Db1 ( Weekly full, cold backup, Noarchive log mode) around 200G took around 18 minutes last sunday. Backups are to local disks.
Db2 ( Weekly full, hot backup, archivelog mode) around 2 Tb takes around 8-16 hours depending on load/data changes.
Db3 ( Everyday full, hot backup, archivelog mode) 40 gb takes 10 minutes.
With EMC there is a lot to look into. Read/Write Cache/ storage raid etc.
Re: RMAN backup performance [message #499921 is a reply to message #499702] Wed, 16 March 2011 12:58 Go to previous messageGo to next message
John Watson
Messages: 4864
Registered: January 2010
Location: Global Village
Senior Member
Thanks, guys.
I'll be getting some tests scheduled when I can (change control procedures......)
Re: RMAN backup performance [message #499979 is a reply to message #499695] Thu, 17 March 2011 01:17 Go to previous messageGo to next message
hkchital
Messages: 128
Registered: September 2008
Location: Singapore
Senior Member
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

Re: RMAN backup performance [message #499982 is a reply to message #499979] Thu, 17 March 2011 01:43 Go to previous messageGo to next message
John Watson
Messages: 4864
Registered: January 2010
Location: Global Village
Senior Member
Thank you for the suggestion, but I can't use multiple channels with SE licences.
Re: RMAN backup performance [message #499987 is a reply to message #499979] Thu, 17 March 2011 02:11 Go to previous messageGo to next message
Michel Cadot
Messages: 60016
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
Quote:
Are you using multiple Channels, Automatic Parallelism ?

Are you reading the question before answering?
Quote:
This is standard edition, so no parallelism.


Regards
Michel
Re: RMAN backup performance [message #499999 is a reply to message #499987] Thu, 17 March 2011 03:32 Go to previous message
hkchital
Messages: 128
Registered: September 2008
Location: Singapore
Senior Member
Aaah .. Michel,

You have caught me not reading the question.

Hemant
Previous Topic: Getting error ORA-19870: error reading backup piece during database cloning
Next Topic: Query on Cloning DB across Platform
Goto Forum:
  


Current Time: Mon Dec 22 03:57:02 CST 2014

Total time taken to generate the page: 0.93986 seconds