How important is deduplication for virtual server backup and does it matter whether you perform source deduplication or dedupe at the target?
The answer to this question depends on your idea of what’s important. Deduplication could be thought of as unimportant since it is certainly possible to make a virtual server backup without it. However, if your goal is to conserve space, then deduplication does take on a level of importance. Deduplication can be especially effective in virtual server environments because of the simple fact that a single host server could be running multiple copies of the same operating system. Deduplication can help to minimize the amount of data that must be backed up.
The location at which deduplication is performed does make a difference. Source deduplication consumes resources on the server that is being backed up. In a virtual server environment, it is usually better to perform deduplication on the target, because you don’t want to consume more resources on a virtualization host than you have to. Those resources are usually put to better use hosting virtual machines.
One big exception comes into play if the backup location is separated from the host server by a WAN link. If you are backing the server up across a WAN then you should perform deduplication at the source as a way of minimizing the amount of data that needs to be sent across the WAN.
This was first published in April 2012