Date: Thu, 15 Jul 1999 09:14:44 -0700 (PDT) From: Matthew Jacob <mjacob@feral.com> To: Nick Hilliard <nick@iol.ie> Cc: radams@siscom.net, hardware@FreeBSD.ORG, stable@FreeBSD.ORG Subject: Re: Fibre Channel Controller Message-ID: <Pine.BSF.4.05.9907150908270.13970-100000@semuta.feral.com> In-Reply-To: <199907151052.LAA19073@beckett.earlsfort.iol.ie>
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> 3) Multi-Initiator on SCSI? Don't make me laugh. Every FC drive has two
> ports as standard. Multi-Initiator is built in.
A word of caution about this- there is a lot of buggy driver f/w for the
dual ports.
> 6) Fibrechannel drives do not consume 50% more than SCSI drives unless you
What does this mean?
> want to compare current SCSI drives with old FC ones.
>
> [...]
>
> 8) FC is bidirectional and is meant to be dual loop so really you have
> 400Mbytes per second if you want to compare numbers. By the time Ultra160
> is stable 2Gb FC links will be available. Where has SCSI to go then? 80Mhz
> I don't think so. 2Gb transceivers are readily available and 4Gb
> transceivers are well on their way.
No, wrong thinking here. This is theory. In practice unless you use
switches you don't have full duplex. I don't know of any FC card that has
the number of connectors to make it true dual-loop (2x{send,receive}), so
that argument is bogus.
A better point to note that the 2GB FC links are coming.
> So what would I buy for my PC, well UltraSCSI of course, unless <company>
> gives me an FC cabinet. Then again if I was buying a couple of terabytes
> then I would go FC, mirroring (RAID1) not RAID5 because drives are cheap
> and write performance is better.
This is my conclusion too, but the figure of merit isn't a "couple of
terabytes", it's "numbers of addressable units".
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