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To use target deduplication, you'll have to install an appliance at each remote site and direct backups to the appliance. After the appliance dedupes the remote site's backup, it can be replicated back to a central site. Because it requires an appliance of some sort, target deduplication isn't appropriate for mobile data.
Source deduplication is backup software that dedupes the data at the very beginning of the backup process. The server or mobile device being backed up communicates with the source deduplication server and "describes" the segments of data it has found that need to be backed up. If the source deduplication server sees that a segment has already been backed up, the segment isn't transferred across the network. This saves disk space on the server and reduces the amount of bandwidth the backup process uses.
Source deduplication can be used to back up both remote sites and mobile users. All you need to do is install source deduplication software on the computer to be backed up and initiate the backup. (This is a bit of an oversimplification, of course, and ignores the challenge of completing the initial full backup.)
Continuous backup of remote data
Another technology that should be considered for remote site and mobile user backup is continuous data protection (CDP). Think
of CDP as replication with a "back" button. Like replication, it's a continuous process that runs throughout the day, incrementally transferring new blocks to a remote backup server. But unlike standard replication products, CDP systems also store a log of changes so that a protected system can be restored to any point in time within its retention period in a few seconds or less. While a traditional backup system (including one using deduplication) can restore a client to the last time a backup ran, a CDP system can restore a client to only seconds ago, since the backup is continuously occurring. A CDP product can be used to back up both remote sites and mobile users because it's also a block-level incremental-forever technology.
This was first published in March 2011