SQL Backups: Deduplication Query

[TSMCON]

Hi
TSM Server v6.3
various TSM clients, v5.5 - v6.3

DBA's currently take a backup of their SQL databases to disk and we then use TSM to backup those files. Those
backups are compressed by SQL during initial backup to disk.

The backups are written directly to a VTL (IBM Protectier) where deduplication processing takes place.

There is no dedupe processing taking place anywhere other than the Protectier appliance.

Because the backups were earlier compressed, i understand i may not be making 'best-use' of the VTL. I am considering removing the compression, and allowing the device to dedupe the data instead. I guess the downside is that as the backups are no longer compressed, they will require more disk space to store the initial backup on.

The databases are not huge, biggest may only be about 50gb

Am i likely to see increased deduplication rates using this method?


Thanks

 

[Phil_02GT]

You will definitely get better ratio by letting the Protectier deduplicate and compress. Compressed data is hard to deduplicate so the Protectier will deduplicate first and then compress.

 

[rallingham]

If you look at the Best Practices Guide from IBM for the ProtecTier, it states that Compression and Encryption must be turned off. No dedupe will take place if compression is on.

 

[TSMCON]

OK, thanks guys. I will have a read