RE: Oracle backups using Snapshot Technology

Hey Dianna,

A little late here, but we have implemented a snapshot backup scenario. Why? We were fortunate to upgrade from an HP AutoRAID 12H (run, Forrest, run!) to an IBM TotalStorage DS4400 (nee "FAStT700"). Our Corporate backups are Tivoli. Tivoli license for Oracle plugin is expensive. User/business requirements are that we have a day-old playground of our ~50GB ERP DB as a workaround for vendor's poor
"what-if" capacity planning in the ERP software. This just screamed
"snapshots!" to our lead SA.

So for our 9.2.0.5.0 DB, we have a nightly script that:

1. Shuts down the secondary instance. (which obviously didn't exist the first time this was run!)
2. umounts it's mount point.
3. Drops the FlashCopy (IBM's FAStT name for snapshot) logical drive.
4. Sets all TSs in the primary DB to begin backup.
5. Recreates the FlashCopy logical drive.
6. Remounts the secondary mount point.
7. Ends backup mode on primary TSs.
8. Tivoli backs up secondary DB MP (and archived redo, backup control file, etc).
9. Starts up secondary instance with recovery.

Steps 6/7 may be reversed -- I forget. Anyway, this satisfies our requirements.

My initial concern was the overhead of block copying while the FlashCopy logical drive is active, which for us is all day. This is made worse by starting up an instance on that logical drive because now not only are there block copies for initial writes to the primary, but also for initial writes of blocks on the secondary. Plus, our secondary is on the same server as the primary, so the penalty for nasty ad-hoc queries on the secondary is almost the same as if it were run on the primary. For us, this was not a problem after lots of testing showed that even with the overhead, our new hardware was still muuuuuuuch faster than our old system. :) I have not heard of a single performance problem related to this in over two years of using it.

Of course, there's a huge "YMMV" here. :) HTH! GL!

Rich

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of DIANNA GIBBS Sent: Wednesday, November 08, 2006 9:45 AM To: oracle-l_at_freelists.org
Subject: Oracle backups using Snapshot Technology

We're looking at implementing a new enterprise backup solution.

Is anyone using "snapshot technology" to backup your oracle databases? If so, could I get more info - O/S, database version, database size, timings for putting tablespaces in backup mode (database mode if 10g), SGA size, good things, lessons learned, comments or thoughts? Have you tested the backup, recovered or refreshed an environment using this technology - any issues?

What about snapshot vs RMAN - any comments?

Thanks in advance.
Dianna Gibbs
Children's Medical Center - Dallas

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