Has anyone ever made an old workstation desktop into a diskshelf. My idea from trolling the internet is to have nothing in the case except my ZFS disks, a molex powered SAS expander, and a power supply. A cheap $25 SFF8088 to SFF8087 expansion slot card and away we go. I am contemplating this because my current daily driver is getting old, but would easily be an upgrade for my current workstation NAS / proxmox machine. The issue is the daily driver is an old Dell Workstation so the case has less than adequate disk storage and proprietary power / motherboard layout so a case swap is non trivial.
I realize I would have to wire a switch for the diskshelf power supply and would need to power it on before booting the primary machine, but that seems easy enough. I could run power between the two so that both power supplies could run off the primary button, but I think I would prefer the single SAS cable between the two?
Without a motherboard to control it, might want to pick up a molex to fan connector, and just run the fans off the power supply.
An inline resistor, like noctua bundles might save them running full speed all the time?
how many drives you thinking? You can get a 4 connector 6GB/s HBA to connect 16 drives directly without a sas expander
then you could get cables to connect 4 SATA drives to a single SFF-8088 connector.
Then for the fans just having some decent ventilation and keep the air moving. If you want to get super fancy you could get a pi zero and use the GP/IO to monitor temperature and generate a good enough PWM to control your fans and adding a relay hat would allow it to turn your shelf on and off though a start up script if you hook it to your PC for USB power or let it poll the network to “see” when your workstation comes online and let it timeout when it “sees” your workstation go offline.
I was going to use a SAS expander because I already have a LSI 4i card. A SAS expander also allows only one cable between the two cases. It may not be the cheapest option, but it uses hardware I already have and keeps things clean(ish).
EDIT:
A thought instead of a motherboard to power the SAS expander, maybe a mining GPU riser kit which can power your card from a SATA or molex connector
Actually, I just converted an old 4U supermicro case into a pure DAS. I soldered some fittings so I just plug in a 12v cable from my main machine into the case in order to trigger the Add2PSU in the DAS. I can post more about it later.
I believe intel SAS expanders have a build in molex power connector which will alternatively power them as opposed to PCIE power, though a riser might be a cheaper option for non intel cards.
I’ve done this. I have 16 disks in an old Fractal case. I found a switch on ebay that connected to the 24 pin power connector and mounted that in the back of the case to turn it on and off and use a couple of PCI slot adapters to convert external SAS to internal. I don’t have any expanders but I don’t see why that wouldn’t work assuming your controller supports it.
I do have an annoying problem where I have to periodically disconnect and reconnect the power on some of the disks because they start getting IO errors. I haven’t got to the bottom of why this is happening but I suspect I just need a better PSU, although it could be the length/quality/conversion of the SAS cables.
Here’s what it looks like inside my server. Basically I have a custom 6 pin GPU cable to the right, but the slot in the PSU power distribution board is 8 pins, so I use that spare 12v and ground pins to send my 12v signal to the DAS. When creating your own connectors, always quadruple check you didn’t fuck up, because it’s really easy to get things flipped around. Creating your own wires and terminating them with connectors is beyond the scope of this post, but you definitely need a quality crimping tool and sharp wire stripper. Moddiy.com is probably the best place to find the various connectors used in desktop computers.
The 12v socket below has the 12v pin/wire heatshrinked to prevent shorts. The ground wire is left exposed since I forgot and it doesn’t matter. For paranoia’s sake, I added an Inline fuse holder with a very weak fuse, since no significant amps should ever go across that wire. The PSU_ON sensing pin for the PSU motherboard header only needs a tiny fraction of an amp to activate.
I have a pair of old supermicro CSE-846 24 bay chassis I’m going to use as a DAS. Here’s the connections in the back of one. The PCIe slot cover the 12v cable is plugging into is a “I don’t like it but I need it done for now” sort of thing. The socket itself fits between the slots just fine, but the nut I used to secure it doesn’t. I have solid slot covers and a decent drill bit set that’s arrived, so I’m going to redo it properly and it won’t need the nut in the front. When I set the second chassis up, I’ll use a 12v cable splitter.
The PSU molex power connecter, connected to a molex to sata power adapter, connected to a sata power to a fan header to power the Noctua NA-FC1 to run the fans. More on that later.
Finally there’s the 12v socket, with the 12v and ground wires ending with a molex power connector. This plugs into the add2psu board. All the board does is detect when there is a tiny amount of power from the 12v pin, which then via relay jumps the motherboard power header. The board had a foam pad on the back to prevent shorts from the exposed solder points, and furthermore is secured and stood off by strong magnets, M3 brass standoffs, M3 countersunk screws, with nylon washers on both sides of the silicon to protect it from cracking and to spread out the stress.
In order to have the DAS fans run at a reasonable speed, I used a Noctua NA-FC1 and the included triple splitter. With these powerful fans, you need to be certain that everything can handle the max amps they can pull, and the Noctua NA-FC1 can handle 3 amps.
I did it with a mid ATX tower case I had with AMD innards. It was a pretty easy project, I just didn’t go with the single power switch mod so it was easier than what you are proposing.
I think the biggest downside is my case could accomodate about a half dozen drives and it sounds like your proprietary Dell case won’t. I would probably pass on that and turn that old machine into a Tor node or something.
