Question : Incremental backup without a full

We are using NTbackup with along with tapes to perform our daily backups. The tapes are rotated on a weekly basis and a new tape is inserted every Tuesday.


On Tuesday nights, NTbackup performs a full backup of the directory.  From Wed-Mon NTbackup perform incremental backups of the same directory.

The NTBackup's full and the incremental backups of the directory both backs up to the same .bkf on the tape.  

At the end of the week, when the tape is to be rotated, the .bkf is near double the size of the directory it has been backing up.  Can someone help me see what is going wrong?

I'm thinking maybe I don't need to execute a full backup job on Tuesdays and just run the incremental all week.  Does anyone know if the incremental backup would perform a
a full back does not already exist on the tape.

Answer : Incremental backup without a full

No, you will need a full backup to be performed periodically...otherwise, the incremental would have no 'start point' to begin with...

When you say the bkf is double the size...how much data is changing?  This doesn't sound illogical to me...