Target deduplication is the removal of redundancies from a backup transmission as it passes through an appliance sitting between the source and the backup target. Both intelligent disk targets (IDTs) and virtual tape libraries (VTL) use target deduplication. The method allows you to use any backup software that the device supports. Target deduplication reduces the amount of storage required but, unlike source deduplication, it does not reduce the amount of data that must be sent across a LAN or WAN during the backup.
Target deduplication requires hardware at remote sites, which is sometimes considered a drawback in comparison to source deduplication products. However, because target deduplication provides faster performance for large (multiple terabyte) data sets, it is typically employed by companies with larger datasets and fewer bandwidth constraints.