The SBUS is architecturally limited to a maximum bandwidth of 65MB/sec.
If we used our DLT7000 compressed maximum transfer speed of 10MB/sec,
then we should theoretically be able to support six DLT7000s. However,
the limitation is in the SBUS bus count itself. The Ultra 2 has one
SBUS shared between four slots. This bus is also shared between all of
the peripheral devices.(Ethernet;SCSI;Serial;etc.) Finally, the Ultra 2
CPU maximum configuration supports up to two 300MHz CPU's. The CPU's
are the determining factor here.
If I assume that you have replaced your SCSI HBA's with JNI FC HBA's,
then you have probably done so for connectivity reasons, and not for
performance reasons. The JNI's will only move data as fast as they are
presented with the data.
The Bottom Line:
Depending on the CPU count and memory installed in your Ultra 2, you
should have no problem supporting four DLT7000 drives with SCSI or FC
HBA's.
Regards,
Michael Gaytan
Solution Engineer
Vangard Technology
> -----Original Message-----
> From: Andrew Steingruebl [mailto:steingra AT pprd.abbott DOT com]
> Sent: Friday, June 09, 2000 10:30 AM
> To: Michael Gaytan
> Cc: veritas-bu AT mailman.eng.auburn DOT edu
> Subject: Re: [Veritas-bu] DLT7000 on FC/AL
>
>
> "Michael Gaytan" said:
>
> >Fibre channel connectivity has essentially moved the bottle neck from
> >the external I/O Bus to the internal PCI bus. (32-bit,33MHz @ 128MB/sec;
> >64-bit,33MHz @ 266MB/sec; and 64-bit,66MHz @ 530MB/sec.) By running
> >multiple FC HBA's on PCI Bus, (E450 supports up to 8) you could
> >potentially overwhelm the internal PCI buses.
>
> Given everything you've said below, and here, any experience with
> Ultra-2's an
> SBUS HBA's in the same sort of configuration? I know we're now
> going to get
> the same throughput on an SBUS HBA as on the PCI, but I'm wondering what
> you've seen as the ratio. I'd like to avoid having to purchase 220's to
> replace my backup servers, when the JNI SBUS HBA I have seems to
> be working ok
> for the moment.
>
>
>
> --
> Andy Steingruebl | e-mail: steingra AT pprd.abbott DOT com
> Unix Systems Admin/Programmer | phone: (847) 935-4728
> Unix/Network Security | fax: (847) 935-0142
> Abbott Laboratories, PPDR&D | post: 100 Abbott Park Road, D472 - AP9A
> | Abbott Park, IL 60064-6115
>
>
>
|
