deduplication and RDM

[jcgam]

Is deduplication supported with RDM? I'm running VMWare 4.1 and Veeam B&R 5.0.1.198 with a Compellent SAN connected via fiber.

To test optimal settings for deduplication I created a copy of an existing linux VM and backed up the original and the copy in a single backup job using the following settings. Both VMs use RDM storage.

- direct SAN access (the backup server has direct fiber access to all LUNs)
- inline data deduplication enabled
- compression: optimal
- storage: local target

The veeam backup file was 65% larger than a backup file created from the original VM only. I changed the storage target to WAN but this didn't make much difference (~5%). Nearly all of the blocks are identical between these two VMs, so why is the backup file so large?

[Gostev]

Yes, it is supported. Otherwise backup file would be 100% larger in this experiment. It looks like on block level the content of RDM is not so similar though (or data is similar, but not aligned similarly on block level). Thanks.