Anyone run into this? I've gotten my tape performance tuned pretty well 
under NetBackup 5.1 MP3 where I'm seeing about 10,000-12,000KB/s on each 
of my 6 tape drives even when doing a multi-streamed backup from a 
single server. Yet when I do a backup to disk, I see decent performance 
on one stream (about 8,000KB/s or so) but the other streams will drop to 
around 300-500KB/s.

I've tweaked my buffers some following some recommendations I got off 
the Veritas website:

NUMBER_DATA_BUFFERS = 16
NUMBER_DATA_BUFFERS_DISK = 16

SIZE_DATA_BUFFERS = 262144
SIZE_DATA_BUFFERS_DISK = 1048576

and I see this performance on both the master server disk pool AND a 
media server disk pool. The master server is a VxVM concat volume set of 
3x73GB 10,000RPM disks and the media server is an external raid 5 volume 
of 16x250GB SATA disks. I'm kinda stumped as to how to even go about 
trying to figure out how to fix/improve the performance on this. I 
figured that I'd be seeing the opposite where I have good performance on 
my disk drives and not so good performance on my tape drives.