Deduplication Query.

NetBackups own de-duplication for media servers is known as MSDP (Media Server De-duplication) - this is what you can use with built in storage on a media server and is what the appliances use.

NetBackup can also use OST devices (third party device / de-duplicaiton software) that is understood and has plugins for NetBackup - in these case the storage and de-duplication work is done by the third party vendor - these include Data Domain, Quantum DXi and even Symantec PureDisk.

MSDP provides all possible NetBackup options such as AIR, Accelerator, Vmware Accelerator etc. but not all third party vendors have OST -Plugins that can do all of these features

Vmware Accelerator only works with MSDP at the moment i believe - it is a big feature of NetBAckup 7.6 but I haven't heard that anyone else has the OST Plugin developed to support it as yet

Hope this helps

Mark gives a comprehensive answer in general, but specifically to answer your query "whether Symantec uses same dedupe technique like EMC (CPU centric)", the answer is yes, it can do CPU-centric, also called server-side (target) deduplication, and in fact does this by default. This means that the server (in this case the NetBackup MSDP server) is doing the CPU work for deduplication fingerprinting.

However it is easy to configure client-side (source) deduplication, where the client (or a sub-set of clients) are helping do the deduplication fingerprinting, which helps distribute the CPU load involved in this work amongst some or all clients. The additional benefit is also that only unique data is sent over the network from client to server (whereas in the server-side / target deduplication, ALL the data is sent from client over the network, and then you throw away the duplicate data).

If you compare dedupe rates between Data Domain and Netbackup MSDP/Appliance I think it will be a draw.