Size of Backup does not come close to the amount of data on the server

[PHead2]

I'm doing full backups and the size of the backup is substantially less than the amount of data on the servers, particularily on Domain Controllers. On these machines the backup size is listed as about half the size of the actual data on the servers.

For the other machines it's not as off. I don't expect the numbers to be exactly the same due to the different ways of calculating the amount of space data is taking up on a drive, but a difference of half seems problematic to me.

Am I worrying about nothing, or is this indicative of a problem with my backups?

Thanks.

 

[Narizz28]

How are you backing up the DC's? Are you backing the servers up one the whole (\\servername) or by the separate volumes (\\server\c$, \\server\?system state).

Also, are the DC's NT4 domain DC's, or Active Directory DC's?

 

[PHead2]

I select the server as a whole, but I did check through all of the seperate volumes and they all get selected.

They are both active Directory DCs, Windows 2000 Adv. Server SP-3.

 

[SQLBill]

Are you doing backup with compression on one and not on the other?

-SQLBill

 

[PHead2]

I'm using hardware compression on all of the backups.

 

[Narizz28]

One thing you could try that might show you if it's a particular volume, is to break the job up into mutliple jobs schedule a few minutes behind each other. I.E. Dlete the job and vreat one for the C$ volume and schedule 2 minutes after you last job, then create another job for the D$ and shedule to munites after that, and so on.

This action will let you evaluate what each volume is reporting separately of the other volumes. If this then shows something "wierd", you can take corrective action. If it proves to show nothing at all, delete the individual jobs and recreate the server-at-once job.

 

[PHead2]

I'll try restoring the files to another server this week and see what I end up with.

 

[jamkey]

How are you determining the Backup Size? In some locations it will list it as space on the tape and others it will list it as the actual raw data. Also, the Media set report was somewhat "broken" in earlier versions of BE but in 8.6 it seems to be pretty accurate (make sure you are reading the VERY last column (may have to scroll over) of the Media set report on the Reports tab.)