It took a little over 3 hrs to write, so it's definitely going to take some time to digest.@NANOFROG:
Thanks big times for your reply. I think I never received such a detailed and helping reply in a forum before, so KUDOS
That's a lot of info to process and I need to think it through.
I was actually surprised to see you replied this quickly (expected ~2 - 3 days actually).
It was based on cost reasons (better use of what you already have, so you didn't have to run out and get another SSD for scratch and possibly a 2nd for Windows).
Using 2x lower cost units for cheaper capacity is a good idea if you've the bays available (sometimes works out, sometimes it doesn't, so you'll have to cost it out and see for the specific parts you're after).
ICH can't really handle more than a 2x disk SSD stripe set, but you will get better performance on the RAID card, and it has the ports (and comes with the cable needed to connect them).
I figured this was the case, from what you posted, but needed to be sure (you were clear enough that the optical disk was external - figured USB though to keep it bootable for multiple OS's).
All you need is a single disk on the ICH, which you can do this at any time (cheap too, all things considered).
I presume this system is being used to earn a living, so there's your logical explanation.
Hopefully this tactic will work, but keep a bag packed and be ready to run for it just in case... Get TM off of that disk, and use the Drobo as your backup solution. If you want to keep TM as well (i.e. backup of the Home folder), then use a separate disk (external, say via the eSATA card).
What size is the Windows disk?
ATM, I'll presume it's 3.5". Unfortunately, I'm not seeing a ready-made mount to stuff 2x 2.5" + 1x 3.5" drives in a single optical bay.
You may need to use the mount you have for the SSD's, and set the 3.5" on top, via something you can do DIY (i.e. use the metal tray off of an old optical drive; just drill some holes).
Other materials can be used as well, but there will be more work getting it sized properly (need to cut as well as drill holes), such as bare PCB material, thin plywood (such as you'd find in a hobby shop for model plane building), or thin plexiglass (hard plastic sheet).
You could also try one of these, but I don't know about the height when stacked on top of the 2.5" mount.
Another note: SSD's don't have any moving parts, so they can be stuffed anywhere with things like zip ties and Velcro.
One last alternative, would be use the 4x 2.5" backplane cage, and get a 2.5" disk for Windows (what I planned in the last post), and attach it to the ICH via Right Angle SATA cable (means buying a disk; SSD or laptop mechanical will fit the bill in this case).
You have options, but it means either buying a disk (nice and clean though), or possibly making a mount. Your choice.
You may have a problem due to the slot configuration in the MP.
Let me explain:
The chipset (X58) has 36 lanes, 32 of which are dedicated to Slots 1 and 2 (16x each), which leaves 4x lanes total. So what Apple chose to do, was use a PCIe Switch in order to share those lanes for Slots 3 and 4.
What this means for slots 3 and 4, is if they're used simultaneously, the speed is reduced per card due to the switching back and forth (idle time + switch latency). Not a problem if you make sure both cards are not running at the same time (or at least keep such instances to a minimum = reduced negative effect in this situation).
Now all the slots in your system are PCIe Gen 2.0, which means they top out at 500MB/s each, so long as the card is also PCIe Gen 2.0 compliant (you need to check this). If not, your speed will be cut in half.
In the case of the RAID card, it is Gen 2.0 compliant, so it would max out at 2GB/s in slot 3 or 4 (usable to start with without throttling on the slot, but may be a problem as you scale up - using SSD's, not mechanical). This is based on 500MB/s for the OS array + 250MB/s for a scratch disk + 350MB/s for the RAID 5 (worst case starting point from what you've posted so far).
What I'd recommend doing, is trying out your second graphics card in Slot 3 or 4 and see how it goes (I presume the eSATA card sits on one of these as well, which is why I mentioned that these two ports are shared).
It would also be useful to know what exactly the 2nd graphics card is, and what you're doing with it (remember, graphics cards cannot even saturate a 16x lane Gen 1 slot).
Details on the eSATA card might help too, though Slot 3 or 4 is the only logical location.
You move the SSD's to the card.
For the existing mechanical disks, you have a few options:
Depending on the eSATA card (both throughput and if it supports Port Multiplier enclosures or not).
- Get a Port Multiplier enclosure (Sans Digital TR4MP; it even comes with a 6.0Gb/s card and is stated to work with OS X <driver support only>), and stuff them in there (useful for another backup location, archival storage <i.e. movie + music library>, and clones).
- Use separate (single disk) eSATA enclosures for the above reasons (keeping OS clones are especially useful).
It's what they've done with the 1680 series. Yes, you can connect drives to it, but they were shared, not independent (can affect throughputs due to shared bandwidth; and the disk count matters significantly). The external port was really meant for using SAS Expanders (can allow you to run up to 128 disks on one card; they're just not that fast given they're sharing 4x ports for bandwidth compared to a 1:1 ratio).I just checked with their website and also with their german distributor, but none of them mention that the 1880ixl is sharing one of the internal ports with the external one. They are saying I can connect up to 12 drives to the controller (8 internal, 4 external). Although the "8" in the name does actually suggest otherwise....
the price difference to the "true 12 port model" you mention is not that big, but you may know how wifes react if you spend money on something that's not for them
So can we confirm this information somehow?
But you should contact Areca directly (phone or email; they're located in Taiwan, but do speak English). So you'd be able to communicate with them sufficiently I think (their English isn't that great, but you can usually figure it out after reading it carefully a couple of times for difficult issues; simple issues/questions are fairly easy to interpret the answer). You'll see what I mean...
But they do know what they're talking about if you have a problem, so don't panic that you're on your own (like you would be with other companies like Highpoint).
