EMC / Data Domain is NOT faster than VTL
"Data Domain says that overall resource use on the media server is reduced by 20 to 40 per cent because of a reduced data copy overhead."
Data copy overhead? This is a patently stupid and nonsensical statement by EMC. There is no such thing as copy overhead - the whole backup process is a data movement process. The data moves through the media server whether it's raw or deduped. Deduplication on the media server creates ADDITIONAL overhead just as it does with the CommVault deduplication. This is basic backup physics. It's also the very same argument that the Avamar sales team at EMC claims when competing against CommVault's dedupe strategy. (They used to claim that you had to reduce data on the host to gain efficiency).
Here are the basics:
The whole point of using a solution like this is to reduce your backup window... so why would you add an additional process that INCREASES your backup window?
Inline deduplication is no where close to being as efficient as going straight to VTL. Many enterprise customers have tested it and inline dedupe (whether from EMC/Data Domain or others) loses every time in head-to-head tests. Why? Because the inline process creates REAL overhead and slows down the backup job. EMC has been getting killed in Enterprise accounts for this (and for the lack of global dedupe and lack of FC connectivity... but that's a different story). So what did EMC do to fix the problem? They split up the dedupe process between the media server and the appliance with beefy processors. The improvement they get is not from the design, but from the chips... and even then it's not as fast as writing at full speed to a VTL. The design is still flawed.
Any process that moves data between point A and point B is fastest without ADDITIONAL processes (like dedupe) in the way. If your backup job takes X amount of time to complete when writing directly to a VTL, any additional processes (no matter the speed of the processor) will incrementally add to the time to complete your backup job.
It's the very worst combination of what CommVault does with media server dedupe combined with the very worst of data domain - inline dedupe.
This new version is a band aid to mask the problems of inline dedupe which is why EMC is touting improvement speeds without comparing it to the speed of writing to multiple VTLs with global dedupe. This is how they are losing in the enterprise. Its why they always test these for customers using small data sets. When the customer wants to test a real full backup set, they balk.