Ancient Thread!!!
...SAS drives are much higher performance, particularly for an OS drive, than SATA drives. So that was an all around win: OS on the SAS drive, data on the RAID 5.
SAS did, and still does have it's place. But it's horribly expensive.
Fortunately, SATA can fill in the void where SAS isn't absolutely necessary, and do so at a lower cost, such as a stand-alone small business or home system. I suspect this is where you come in, unless you're trying to salvage your existing drives (I do see you're interested in a newer card).
SATA based SSD's can outperform SAS based mechanical disks as well, so SAS may not have a performance edge, even when compared to the fastest spindle speeds available.
Without further specifics though, I can't really be certain if switching to SATA is the right move for you or not. Certainly cheaper, but if it's running an absolutely critical system, then SAS may be the better choice (i.e. must have as close to 100% uptime over the system's entire lifespan).
This is the single-point failure mode people often overlook with RAID. If your RAID controller goes out and you cannot replace it with an identical controller, you've lost your disks. With my setup, I can only use a 2008 vintage Mac Pro with the 2008 vintage RAID card to read the array. Eeew.
You're not wrong, but in most cases, there are financial restrictions that have to be balanced.
So taking failure statistics into account, you'll find that the RAID card is far less likely to die than a disk, which helps tremendously for many users (those that can't afford to have multiple cards with identical arrays, and then repeat the entire system for a true n=1 or better redundancy level <entire system dies, another takes over it's job immediately>; this sort of implementation does exist, but isn't common but for critical systems within companies that can't afford not to do this - think banking data for example). It even gets more extreme... (think multiple facilities that contain identical systems and data but located in different parts of the planet to avoid total loss in the event of a natural disaster).
So my big question is what to use for an internal RAID card. The ATTO cards look to be over $1,000, the Areca $700, and none of the cards I looked at from any vendor look like they'll reach the mini-SAS cable inside the Mac Pro chassis.
They're it in terms of proper RAID cards that work in a MP. LSI *might* have a model that would work after being hacked, but I wouldn't go that route. Too risky IMHO.
(I'm sure I can get a mini-SAS cable extender but I'm worried about cable length.
Such a product is available, and works (been done before).
Newer has their MAXPower RAID and Highpoint has their RocketRAID and I'm sure there are others that are less than half the price of the Areca. What am I really getting for the extra money?
MAXPower is just an RoC IIRC (what do you expect for under $300?), not a full fledged RAID card, and Highpoint is something to avoid like the proverbial plague due to support as bad or worse than Apple's (horrible stories in here by users that tried a Highpoint; couldn't get firmware or drivers for example).
As per the cards from Areca and ATTO being as expensive as you're seeing, it depends on exactly what you need. They do offer suitable cards for less money if you don't need high port counts or perhaps the latest models (not enough details to be sure what to recommend yet, though it seems as if a 4 - 8 port card is all you'll need at most).
The extra funds spent on an ATTO or Areca get you real support, better features (in terms of ability to recover a failure), and better performance. So it's not a waste.
Personally, I recommend 4 more ports than you need now, as it makes the first round of expansion cheaper (just add more disks) vs. replacing all of the disks every single time. Much cheaper in the long run.
Next question is about on-card batteries. The ATTO card does not seem to have a battery or an option for one. The Areca has an option for one. Are they doing something else to recover from a power loss or do I need to get a battery? I have a UPS but the fact that my Apple RAID card keeps complaining about a disorderly shutdown makes me worry that the system is removing power before the writes complete and the UPS is not going to help there.
Card batteries are nice, but the UPS is far more important, which is why ATTO seems to no longer make card batteries available (lack of sales, as educated buyers know this, and have backup power systems we'd both drool over; UPS + generator system that's also redundant).
Worst case, the existing data is still there, but a process that was lost due to say loss of power on the UPS, would have to be repeated.
There are additional features in cards such as ATTO and Areca. For example, they keep a copy of the partition tables stored on their ROM's in the event the PT's are wiped out from the disks.
As per the Apple card issue you describe, it's particular to that card (i.e. card battery isn't able to maintain a charge, thus it logs an error when the charge isn't detected). Even though the system is fine (assuming this is the case, as you'd have had all kinds of hell in the form of data rebuilds every single time you turn on the system).
