Is the size of a "backup-to-disk" file permanently set?

[BernardJL]

We are using "backup to disk" devices for all our backups.  We have done so for some time and the operations are stable.

However, it appears that when the "backup to disk" (B2D) files are recycled, they same to keep the same size that they had when they were first created.

All of our B2D devices are set with a 100GB maximum size. 

We do NOT "Allocate the maximum size for backup-to-disk files" 

But we are seeing B2D files marked "Media full" with much smaller sizes.  An example is one that is showing "Media full" but showed:

Data:  1.24 GB

Used Capacity: 1.2 GB

Available Capacity: 49.38 GB

Total Capacity: 51.1 GB

What is going on here?

We have these variable sized B2D files with "Media Full" and sizes well under the maximum allowed.  There is room on the drive so why are they marked "Full"?

Just from observation it appears whatever size the file is at the time it is created, that becomes it's maximum size.  If the file is re-used, that size remains with it for the life of the file. 

Is this correct?  What are we missing since this process is causing backups to be spread over lots of files when the total backup is well below the 100G maximum.

Your help and advice is appreciated.

[Ken_Putnam]

If you hadn't said this  

We do NOT "Allocate the maximum size for backup-to-disk files"

I would guess that the Max sets per BKF was coming into play, but your statement blows that out of the water

I have set the support flag to draw this to the attention of the Symantec folks for you

[BernardJL]

Thanks, Ken, we appreciate your quick reply. 

[pkh]

What is the version of BE that you are using? 

[BernardJL]

PKH, this is latest version 2010 with all the current updates from Live-Update applied

Thanks for your interest in this.

[pkh]

I too am using B2D and my .bkf files sizes changes when they got re-used.  Are you appending them?  If so, try overwriting them.

[BernardJL · Accepted solution]

Sorry for the slow response we have been quite busy here.

PKH, we are not appending to backup to disk files.

But at this time the problem is "solved". 

What appears to have corrected the problem is we have been on a program of "erasing" backup to disk files that are ready to be overwritten. 

It appears as we "erased" the backup to disk folders, they then started to act the way we expect.  The size grows and jobs are now running with at most three backup to disk files.

Previously we had some jobs running with 15 backup to disk files on a backup of small desktop machines.

It took some time before the hundreds of small files moved into "overwritable" and we could erase them.

We also deleted quite a few number of these files since they were not needed once the file sizes expanded.

We don't have any idea other than perhaps these backup to disk files had some information in them limiting the size. (?)  The erase re-created that information.

The mystery is not solved but the problem is gone.

Thanks for to everyone for your helpful suggestions, your efforts are greatly appreciated.