we are backing the Dedup folder storage to Tape from Shadow copy component . Dedup storage is 1.9 TB and the C: drive of the BE Media Server is 600 gb appxomately and 400 gb data - Tape 1.5 TB 6 tapes have been used i.e, more then 6 TB of data has been wrritten and the backup job is asking for additional tape .. Remmember the data sized written to tape increasing gradually.
So our question if we backup the dedup storage using Shadow copy component will it rehydrate the data or it will go straight to the tape the way it is.
From your post I understand that you are actually not duplicating the data but backing up the Dedupe Storage from under the Shadow Copy component.
Well in this case the Deduped data will NOT get rehydrated and your backup size should be as good as the size of actual Dedupe folder in addition to your C: drive space used.
Please check if the data is actually getting written to those tapes which are used previously. Also if possible post the job log for review.