First backups to tape - question re incrementals

[McKITGuys]

Hi,

Have just set up our first backups to tape. The jobs are reverse incremental jobs that have 14 restore points; they run all week and then they are set to produce an "Active Full backup" on Saturdays. I have checked the option "Archive incremental backups to tape" for that option in the tape job settings ("incremental backup" step).

I have the tape job set to be chained onto the backup job so it starts after the backup jobs complete. This works.

After a week, when I browse to the tape, it shows 2.2TB used but then in the details it shows 4 jobs each of 1.0TB and a 2nd job in the batch at 4 x 99GB ea.

I would have expected to see the 1st job at 1.0TB and then smaller jobs that just store the incrementals. But it seems it might have stored about 4.4TB.

What am I seeing here - it is actually storing 4 full backups or just storing incrementals but saying they are 1.0TB? I would have expected something like 1.0TB the first day then a much smaller file on subsequent days.

Thanks for any insight.

Albert

[Shestakov]

Hi Albert,
Backup to tape job writes on tape new restore points found from the previous job run. Reverse Incremental method on the primary job produces a backup chain that consists of the last full backup file (VBK) and a set of reverse incremental backup files (VRB) preceding it.
Thus if you run tape job just after the backup job it always copies on tape the full backups.
If you want to save tape space and copy incrementals instead of fulls you can either change the backup method to forward incremental or run the tape jobs more rare.
Thanks