OT: Torn between SCSI and SATA for RAID

[cknipe at savage.za.org]

Hi,

I've been spending the last couple of days extensively looking at various
options for RAID and getting some storage system in place.  Performance is not
really a BIG issue, but I also don't want to have things hecticly slow either. 
This will be a NAS type of implementation so speed would be bound by relatively
speaking slow network connections in any case... 

Now first things first as well, I did look at Fiber Channels too - and the
tecnology is just to expensive and complex for a home type implementation that
I want this for.

Ideally, I'd like to start at 2TB of storage (yes, those movies must go
somewhere!), but I'd like to be able to grow this as times go by... I also
definately want redundancy on the data, as I just lost 80GB of precious data
when ironically, a 160GB SATA Seagate went out under me.

Now SCSI I know, is more expensive than SATA.  Whether it provides beter
performance than SATA I'm still uncertain off, but gut would tell me that due
to the cost factor, SCSI *should* run away as far as speed is concerned.  But
also as I said previously, speed and performance is not a priority for my
implementation and therefore it has very little weight.  This makes me look at
SATA then therefore.

My problem with SATA, is the whole 1 Port, 1 Drive scenario.  I've looked at the
Adaptec 16 Port SATA Controller.  The reviews I managed to get on that card on
the Internet, paints a very grim picture.  Buggered Firmware, the controller
destroys drives, and general sluggish performance.  Is anyone using this card
that can perhaps give me a better picture?

Given than the 16 Port (for now) is out of the question, I have a 8 Port, 4 Port
and 2 Port (which isn't really worth looking at even) available to me.  Now,
even with a 8 Port card... Let's look at what I can achieve:

Ports 1+2: 750GB Seagates (Biggest available), 1.5TB <- I'm short on my 2TB
Initial
Ports 3+4: Mirror of 1+2

Already, I am coming short of what I want to achieve, and I also have no
expansion available to me for upgrades... 

With the 16 Port cards, what I want to achieve becomes quite possible, up to
easy about 6TB of data - but I risk loosing drives *IF* what I read about the
card is true.  Also a gamble, considering the relatively high price of large
SATA drives.

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.

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'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?

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.