with no network to worry about, you should be able to get all 7 of those drives 
backing up raw data a lot faster than 4-5 MB/sec!

My first thought would be to turn on multiplexing.  Gradually increase it and 
watch your backup speed - you should see speedups and then a point of 
diminishing returns as you increase the max MPX value.

Otherwise I'd follow some of the other suggestions from people: sar, iostat, 
ask your EMC guy to verify that you're not taxing the disks in the cabinet...

rob


At 12:13 PM -0500 11/1/00, Porter, Eric wrote:
>Rob,
>
>Answers to your questions are below.  
>Your comments/suggestions (or anyone else's) are appreciated!
>
>Thanks
>
>Eric
>
>**** Where is the data coming from as it's being written to these 9840's?  
>
>The data is being backed-up out of raw logical volumes.  These volumes are
>on the same server as netbackup  (i.e. local) (They are copies generated
>using emc timefinder).
>
>**** How many 9840's are you using for backups?
>
>I have 8 drives, I am using 7.  The scripts I am using split the list of raw
>logical volumes into 7.  Then we start 7 backups each to tackle one set of
>raw logical volumes.  The 8'th drive is reserved for backups of oracle
>archive logs (done hourly).
>
>**** Where is your data coming from?  Is it local on this media server, is
>it on a SAN, is it on one or more segments of your LAN, etc?  
>
>Local for the important data  (about 2 Terabytes).  
>Some less serious stuff originates on a dedicated switched 100M Ethernet
>(running full duplex).
>
>**** Are you configured to use Multiplexing?
>
>No... I am pushing a raw partition from the same system I figured
>multiplexing would hurt not help.
>
>**** with a 9840 drive (transfer rate of 10-20 MB/sec depending on
>compression AND STREAMING) it would be real easy to 'underfeed' your drives
>and therefore cripple your performance.
>
>If the numbers in the netbackup GUI are to be believed I am getting 4 -- 5
>MB/sec per tape drive.