How much “upfront” capacity does deduplication require?
This is not a question for inline deduplication systems, but it is for a post-process. Post-process methods require additional capacity to temporarily store duplicate backup data. How much disk capacity is needed may depend on the size of the backup data sets; how many backup jobs you run on a daily basis, and how long the deduplication technology “holds on” to the capacity before releasing it. Post-process solutions that wait for the backup process to complete before beginning to deduplicate will require larger disk caches than those that start the deduplication process during the backup process.
