Compression problem

[jahwah]

Hello,
I have Backup Exec 11d installed on 2 servers and I have to backup virtual machines. The VMs run in VMware Server and the 2 servers are exactly the same. When I backup up the first server, I backup 2 VMs (60GB), the compression rate is between 3:1 and 4:1 and when I try to backup 2 VM (40GB) on the second the compression rate is 1:1.
I run backup with bemcmd and script, so configs are identical on both servers.
And compression is possible on the second server because when I backup one of my VM(15GB), I suceed with a compression rate of 3:1 (the 3 other VM suceed with a compression rate of 1:1).
Does anybody knows what should be wrong with my second server?

Thanks.

Antonin.

I have 2 Dell PowerEdge 2950 with Windows Server 2003 SE (32 bits) and DAT72 drives.

[SteveVRTS]

I think that it's most likely that the compression is just not reporting correctly.  It is practically impossible to get 2:1 compression much less 3:1 or 4:1.  Backup Exec probably just thinks that the tapes native capacity is smaller than it actaully is.  This will not cause BE to write any less data to the tape.

[jahwah]

I think I have 3:1 compression rate because my files are preallocated disk files. What I mean is that files are about 40GB on servers but in VM there is only 10GB of data.
Tapes are new and 36GB native. One strange thing is that with the same tape, the same backup script and the same files to backup (a 15GB VM) I have different result. The first time I ve got 15GB on my tape and an other time I ve got 5GB on my tape (I did full backup with hardware compression).
Is there any tools to check the performance of my DAT tape ?

Thanks.

Antonin

[SteveVRTS]

There are no tools within Backup Exec to check the performance.  You might want to try the backup with NtBackup to see if your results vary.