August 18, 2011 at 3:41 pm
Hi, I have read some posts about backup VLBDs, but I did not find one that talk about backing up real VLDBs. Therefore I going to show a scenario that I manage with some difficult to discuss about how to backup databases bigger than 10GB.
I'm managing a SAP Database with 11.5 TB and growing around 300GB per month. SAP do not allow me to create multiple filegroups, so I have just the primary filegroup.
So far I'm managing this thread taking one full backup once a week, daily differential backups and backup logs every 15 minutes.
Every backups have SQL compression enable and every backups are done straight to a EMC Fiber channel disk through HBA.
Now the time to take the full backup is increasing constantly and I believe that I wont be able to use the same solution in 8 months.
Backing Up the datafiles separately is not a good solution because there are 64 files and manage multiples backups for a single database will drive any DBA crazy .
O know that many DBAs manage databases bigger than 30 TB, and I will be glad to learn how those people take their backups.
I researching solutions that resides inside the storage, appliances and 3 part tools that takes these backups, but many providers promises things that they can't deliver.
Does anybody deal with a similar scenario? And How are dealing with it?
Regards
Eduardo Pin
August 19, 2011 at 3:50 am
Backing up databases tends to be limited to the subsystem speed and bandwidth. You can create your backup across multiple files, see this sqlcat post for details http://blogs.msdn.com/b/sqlcat/archive/2008/03/02/backup-more-than-1gb-per-second-using-sql2008-backup-compression.aspx
It's a while since I backed up 10TB databases and then there wasn't too much issue to get it done in a specific time.
It's really a matter of scale with a lot of limiting factors. If you have a 16 core box I suggest you start with 8 backup files and work it from there. I'd suggest you might look at teaming your HBAs to the backup drive, in tests I could saturate 4GB bandwidth quite easily. Calculate your current stats and monitor the bandwidth vs the theoretical bandwidth ( gbs/time ) check if your disks are the bottleneck - raid 5 or 6 will not be optimal, neither will 7.2k spindle speed. It might sound expensive to use raid10 for backups but you'd be surprised the difference it makes if you have a speed/time issue.
You might want to consider adding SAS DAS units ( san's are ok but their performance is usually ( well almost always ) poor compared to directly attached storage ) http://www.eurostor.com/english/ES8200S.E.php?SECT=RAID this unit will take 24 disks, say 450GB x 15k = 5TB per unit raid 10 - a couple of these would probably do the job, I suspect.
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www.grumpyolddba.co.uk
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