OT: Torn between SCSI and SATA for RAID

[Atom Powers]

>
> Another thing that I read that I'm not completely sure about.  Some of the
> Adaptec SCSI Cards advertises a max of 30 devices - some even more.  Excuse the
> ignorance, but does the SCSI Bus not allow for a max of 8 devices?  Do these
> cards then feature multiple buses to connect the cables to?  If so, SATA will
> obviously not be able to provide something like this.

I am not that familiar with SCSI protocols, but I imagine the
Ultra-Wide SCSI bus can probably address 32 devices ( 31 drives + the
controller ).

> Now comes my question... Uhm.. Can SATA RAID Controllers be 'linked'.  Say, I
> but 4 x 8-Port Adaptec SATA RAID Controllers... 2 x 8 Port Cards = 16 Ports for
> 1 RAID 5 Array (@ 750GB Drives, 12TB Max).  The other 2 cards, to mirror.  I
> know that I can use one Controller to mirror another, but can I extend a array
> across multiple controllers... And then naturally, just HOW much slower does
> the array function?

I imagine you would probably have to use software raid at that point.
And even if you would use two controllers togeather (SLI for RAID?)
you would be limited by the PCI bus.

>
> I've seen some comments and posts (esp. on slashdot) made where people go about
> running massive arrays successfully on SATA.  Given the limits on the Ports at
> the controller, just how is this achieved?

Probably with softawre RAID. With software RAID you can even mix drive
types, like SATA, PATA, SCSI, USB, etc. But it's much slower.

> Sorry that this is so OT, but I hope I'd get some good answers.  This is
> definately not something that's been discussed allot before considering the
> amount of info I got after spending a number of days on google...
>
> --
> Chris.
>
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--
--
Perfection is just a word I use occasionally with mustard.
--Atom Powers--