keep in mind that the bandwidth limits on a 32 bit, 33Mhz PCI bus are
132 MB/sec. That's the biggest limit I run into in my backup
environment, and someone else mentioned it. That's the agregate for
all devices on the bus. If you have a network card and modern tape
technology, you can pretty much max out that bus bandwidth with just
the network reads and tape writes. On one of my media servers, I'm
quite happy if I get 40MB/sec in from the network and write (inline
tape copy) that out to 2 tape drives. That's pushing the bus at
120MB/sec.

-Charlie

On 7/27/05, Jack L. Forester, Jr. <jack.l.forester AT lmco DOT com> wrote:
> I may be getting some new HBAs to put into my master servers.  They
> would be dual port cards.  Presently, my tape devices are on an older
> JNI HBA which requires me to reboot the server (Sun E450) to add
> devices.  As an additional bonus, the new HBAs would be 2Gb with the old
> ones 1Gb.  I'm considering moving the tapes to the new HBA.  However,
> the main reason we are going to get the HBAs is to attach to our
> enterprise SAN for disk storage.
> 
> Now, to get to my point, I'm aware that it's usually considered bad form
> to put tape and disk on the same port of an HBA.  What about tape and
> disk on different ports of the same HBA?  I would guess that if the card
> has sufficient bandwidth and the ports are truly independent of each
> other (not sharing any settings) that this configuration would be OK.
> 
> Any thoughts?
> 
> --
> Jack L. Forester, Jr.
> UNIX Systems Administrator, Stf
> Lockheed Martin Information Technology
> (304) 625-3946
> 
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