EMC DataDomain Oracle Backup Deduplication Statistics

A real quick post today, as I was reviewing some of our DataDomain statistics.  Below shows the deduplication information for an Oracle database file (~16gb) that was backedup via RMAN to our DataDomain via NFS mount point.

DD01# filesys show compression /backup/db/xxx/xxx/xx6e_1_1
Total files: 1;  bytes/storage_used: 59.1
       Original Bytes:       16,252,249,684
  Globally Compressed:          954,839,915
   Locally Compressed:          272,055,847
            Meta-data:            3,009,088

bytes/storage_used: 59.1 =	Compression and Deduplication ratio
Globally Compressed Factor = 	Pre-Comp / (Size after de-dupe)
Locally Compressed Factor = 	(Size after de-dupe) / Post-Comp

From above you should be getting an idea of the deduplication, but lets follow DataDomain’s formula

Reduction % = ((Pre-Comp – Post-Comp) / Pre-Comp) * 100

Now put in values from our above example

16,252,249,684 – 272,055,847 / 16,252,249,684 * 100 = 98.326%

That gives us a 98.326% reduction!

Basically what I am trying to say is that if you are not doing some sort of deduplication + compression on your Oracle backups, you should look into it.

Note(s): The above information is from a system running Data Domain OS 4.8.1.0-175623.  Also, remember that deduplication savings grow as the same types of blocks are written.  This system has been in production for over a year.  We have about 1tb raw of Oracle data being written to the DataDomain which helps the dedupe ratio.

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~ by Kevin Goodman on October 11, 2010.

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