I have created a protection group for file server and taking backup of a share on tape drive.

under protection method--> I chose I want short-term protection using : tape

retention range: 1 week

frequency of backup: daily

backup mode: full and incremental

so full backup on Saturday and other days incremental backup.

I have around 700 GB data size.

I have shortages of tape. from recovery option: I saw in this month on 12thOct, on Saturday it run full backup. It took one tape [say tape 1]

on the next 6 days it run incremental backup on another tape.[say tape 2]

again on Saturday for full backup it took tape 3 [tape 3]

again to run incremental backup it is asking for free tape. and back up failed.

in this way I am wasting space on tape. data size is 700 GB, tape size is around 3 TB.

I can see there is option in 'optimize usage' where I can mention under advanced. write period and expiry tolerance.

i believe I need to modify these settings.  please suggest if i want daily incremental backup and full backup on Saturday with 1 week retention and reuse the same tape or second tape instead of waiting for more tapes

Hi,

It is currently working as designed for tape library.

See the following TechNet page:

How DPM Uses Tape Libraries
http://technet.microsoft.com/en-us/library/hh757885.aspx

Short-term tape "full and incremental" option

The full backup will require a free tape for each scheduled job, and the incremental backup for all data sources will be appended to a single separate tape.

As tapes fill up, new free tapes will be allocated.

When the next full backup occurs, it will require another free tape, and subsequent incremental backups will be appended to another free tape.

So basically, you will need three sets of tapes for a 1 week retention range.