I’ve been following this from the other site to here and the UK laser site too. I own a rack full of Xserves with seven (7) Xserve RAID’s, almost all maxed-out, so these mods are of great interest: to my knowledge, nobody has attempted anything like this before and documented it so well.
I suspect that the modders have hit the snag where the new backplane not only needs extremely fast I/O for 14 HDD’s — but also requires a hell of a lot of power, bearing in mind that the Xserve RAID had 2 x 750w modular power supplies that Apple installed for good reasons (including a bank of fans all housed together). I don’t know if there are 1500w power supplies out there small enough for this job, do you?
If they can’t get that beautiful-looking backplane to work properly with 14 x HDD’s, they’ll hit more problems trying to get by without it altogether.
One is that the motherboard only has 4 x SATA so they’d need 2 x 8-port RAID cards to talk to all 14 SATA HDD’s (8 x SATA ports on each RAID card), in either RAID or JBOD, but the price of the cards is/was prohibitive.
Alternatively (or simultaneously), the realisation hit them that the number of PCI/PCIe slots on the mobo are limited and, worse, all run at different speeds. For example: typically users would put the video card in x16 slot, Fiber Channel card in x8 slot, NIC ethernet card in x1 slot, depending upon the physical size/specs of the motherboard. It’s my fear that they need an x16 lane slot for video and TWO (even three) x8 lane slots for RAID cards and they, perhaps, couldn’t find a motherboard small enough which is manufactured with those specs.
Additionally, they could have realised that the caddies bizarre SCSI interface was not going to willingly/easily talk to their fabulous new backplane as simply as they’d hoped.
Those are my guesses, unfortunately.
Where they did score huge successes were in the creation of small, snugly-fitting PCB I/O SATA→SCSI boards for the caddy interface; and the manufacture of that gorgeous-looking backplane.
I would like some of those little PCB I/O boards (assuming they’re tested and work perfectly).
Whilst the Xserve RAID’s are the best looking RAID/NAS arrays ever sold, they’re old now (discontinued between 2004 and 2008; three models in the range), and the big problem is that, even with the 1.5 Firmware, they only take Ultra ATA/100 (ATA-6) hard drives up to a maximum capacity of 750GB each. You can imagine that those are becoming increasingly difficult and expensive to source for spares/replacements and, typically secondhand, their long-term reliability tends to be a bit iffy.
Replacing them with comparatively inexpensive SATA’s would extend the life of these beauties for another five years maybe. Getting rid of the 750GB firmware limit would be amazing but will, alas, never happen.
Hopefully, the modders just got distracted — but I fear the worst, sadly.
I don't see why you can't just pull out all the old xserve/raid hardware and fit new hardware inside. The xserve is probably a bit easier given you likely don't need to build custom PCB (although the ones created here in this thread by OP for the RAID drive bays is beautiful). The only issue you'd need to work out would be getting the IO front panel + LEDs working properly.
My goal is to build a modern hackintosh using the xserve case and upgrade an xserve RAID to work with modern HDDs. At the end of the day, you're just using the chassis, and people build their own servers and NAS's all the time. If you're trying to fit server hardware in the xserve RAID while also utilizing the front HDD bays... then perhaps that's a different story.