Opinion

posted on 22 May 2008 17:34

I'm currently trying to get a good grasp on how EMC's new deduping products compare to Data Domain's and have been looking at the D690 and EMC's DL3D 3000 and 4400.

Here is a comment from Data Domain's marketing VP, Beth White, which I'm passing on verbatim: "In the Quantum 7500 / EMC DL3D architecture, the dedupe speed is the bottleneck."

"If you have to finish in a day to get the system ready for tomorrow's backup, the effective speed/capacity of the system is gated on this. In the high end of these products, that seems to be 150 MB/second, or about 540 GB/hour -- or about 13 TB in 24 hours. Neither vendor seems to advertise this spec, though it's the key bottleneck to configure around. To dedupe their whole 150+ TB capacity, you'd need a backup window of greater than two weeks."

"The DD690 offers more than twice this rate at 1.4 TB/hour, so more than twice the effective capacity."

"The DD690's inline dedupe speed is the same as the non-deduped speed of the DL3D 3000. If post-process is no faster, why bother?"
[You'd bother changing to post-process dedupe as a way of keeping backup speed high and not lengthening the backup window I think.]

"Nothing has changed. The 7500 and DL3D systems are not dedupe systems, they're normal VTL designs, giant disk systems as a short term I/O buffer to tape. You can't use their rated speeds for configuring either dedupe or replication. EMC is still about selling more disk than you need, and Quantum is still about selling tape."

Beth refers us to a URL for more information: "See this link from Curtis Preston:
http://www.backupcentral.com/content/view/166/1/>http://www.backupcentral.com/content/view/166/1/ "

^{[Chris Mellor.]}