Having just gone through that (Albiet with Qlogic) this is what I did:

Make sure the st driver is set to a reasonable buffer size (I did this in 
/etc/modprobe.conf):
options st buffer_kbs=1024

echo "1048576" >/usr/openv/netbackup/db/config/SIZE_DATA_BUFFERS
echo "1048576" >/usr/openv/netbackup/db/config/SIZE_DATA_BUFFERS_DISK
echo "16" >/usr/openv/netbackup/db/config/NUMBER_DATA_BUFFERS
echo "16" >/usr/openv/netbackup/db/config/NUMBER_DATA_BUFFERS_DISK

echo "kernel.shmmax = 268435456" >>/etc/sysctl.conf

echo "65536" >/usr/openv/netbackup/NET_BUFFER_SZ

Doing this, I am able to hit 70-80MB/s to the tape from my DSSU, and I 
think I COULD actually go faster, but my DSSU is limiting it.

Someone else amy have better values for these to improve it more - I would 
love to hear them also.

Jason

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Jason Slagle
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On Wed, 30 Apr 2008, Justin Piszcz wrote:

> I am only seeing 8-10MiB/s directly from RAM (/dev/shm) where if I write
> the same data to an LTO-3, I see regular speeds, 60-90MiB/s no problems?
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