> 
> Thanks for the response, Paul.

No prob

>   I have a policy (MS-Windows-NT) that takes Diff-Inc backups 
> every day
> except Sunday, which is when it takes a full.  This produces 
> one job (I
> was under the mistaken impression that Multiplexing allowed one job to
> run to multiple tapes.  Thanks for correcting me). 

MultiPLEXing allows multiple jobs from one or more machines to run to
ONE tape.
Primarily for fast tape drives and slow clients.

MultiSTREAMing allows multiple jobs from one machine to run to multiple
tapes.
Primarily for fast clients and slow tapes

> That job has been
> running between 19-21 hours(!!).  I need to shorten that run 
> time.  This
> is a Windows File Server.  The total backup size is about 
> 750GB.  Right
> now the policy is configured as follows:
> 
>   Policy stuff:
>   Limit Jobs per Policy = 4
>   Allow multiple data streams = Unchecked

This is ONE machine?
You want multiple backups jobs from one machine to go to multiple
drives, correct?
Eg:
C:\ to drive 1
D:\ to drive 2
Etc.

Here is your prob. You need to check "Allow multiple data streams"

And your "Backup Selections" list should look something like:
NEW_STREAM
C:\
NEW_STREAM
D:\
NEW_STREAM
S:\

Etc......
If your drives are not different physical disks, however, this may
actually hurt performance.
You only want to pull maximum of 1 stream per physical disk.

> 
>   Schedule Stuff:
>   Type = Full Backup
>   Media Multiplexing = 4

Another prob. Set multiplexing to 1. (setting multiplex to 4 allows 4
backup jobs to go to one tape.)

> 
>   
>   Any suggestions on shorting the backup time?  Any more info I can
> provide?


What type of tape drive? 
Gig or Fast Ethernet?
Are NICs forced or set to auto Negotiate?

That's a lot of data, if you're not prepared for it...
I'm currently backing up approximately that much data, split between 2
win2k3 clusters.
Each cluster has a RAID5 diskset with about 1TB of space available.
Each machine has a GigE NIC dedicated to backups. (separate VLAN from
production networrk traffic)
I'm pulling 2 streams (different driveletters) from each RAID5 diskset,
(only due to logical naming) then multiplexing the two streams onto a
single LTO2 tapedrive, getting about 50 Mbytes/sec per tape.

We had some significant issue getting these machines up to
speed.......Antivirus was a HUGE speed killer.

Paul