Supermicro Case and Rails (#P6)

Supermicro – the case manufacturer of choice for people with money. :lol:

This is not so much about Wan Hung Lo price ranged products, but rather about construction techniques. And it’s not even about “we made it this way because it’s the cheapest” – it’s about design that yields the most profit for the manufacturer. Vendor lock-in and all that stuff.

Well, I’m more of a Chenbro guy for reasons that I’ll explain in a bit, but I recently did a classic Dave Jones dumpster dive (with permission), from which I got not one, but four Supermicro cases. Two 836 4U 16-bay units, some 2U thing and one 1U pizza box. The latter two sort-of had to go for damages to board and case (and friggen proprietary Supermicro form factors!), but the 836s are still here. They suffered a bit as well, but I find them usable after cleaning and some restoration. And this is about getting one of them ready for use.

First off, thanks Supermicro for evolving your cases without changing their name. Yeees, technically those have changed to reflect that. From 01-SC83618-XX00C001 to 01-SC83618-XX00C103. Now that’ll let everybody know that these are basically completely different cases, right? They still carry 16 pcs 3.5″ SAS/SATA drives and they probably share the same status panel PCB. They also share the power supply tunnel metalwork, meaning power supplies are physically interchangeable. But that’s it. Drive caddies? Likely compatible, but design and colors changed, as did the entire chassis front. Front DVD? New fits old, old doesn’t fit new, moreover changed from bridged PATA-SATA to native SATA. Front floppy disk drive? Removed entirely (well, about time), but the slot is still there – needs physical modification to hold a 2.5″ drive or probably an expensive adapter kit to do that the right way. Front panel connector? Compatible (I think?), but length has changed – Supermicro decided that it is a better idea to place the board connector on the opposite side of the EATX-sized PCB now. SAS backplane? Changed from direct attach (SAS836TQ Rev. 2.0) to expander-based with daisy chaining (BPN-SAS2-836EL2); also changed mounts – old fits new when using reasonable force and a few tweaks to the screws, new doesn’t fit old due to protruding mounts. Rail mounts have changed as well (shown later) – physically incompatible on the case, totally different construction on the rack side (MCP-290-00014-00 doesn’t even have ball bearings?), and due to the large chassis width (W-H-Y?) basically entirely incompatible with any generic rails out there. And of course power supplies have changed to some more efficient models that still have their fans spinning in idle mode (using 15 Watts!), the power distribution units have changed, and the air ducts (with more parts that need to be broken off to fit foreign motherboards) and board mounts have changed due to newer boards with newer sockets and different cooler mounts. Some of it is compatible, some of it isn’t.

Rant aside, back to rail mounting. This is why this became a project post instead of a ten minute job that one doesn’t need to talk about. I’ve had Chenbro cases before and they were mounted in small 16U movable audio racks that are too short to fit the entire case. For Chenbro rails, that’s no problem – very wide adjustment range, and if that still doesn’t fit your needs, you can dismantle them (standard screws, no fuckery) and reverse mount one part. That way, you can basically mount to every pair of rails that is further apart than two times your screw length.

With Supermicro rails, that’s not so easy. They sell different versions in terms of adjustment length, and they mean it. I didn’t have the choice because one pair was included in the dumpster, and I was determined to not spend over 80 bucks on (not-even) fitting rails. The Chenbro rails were 30€ and 36€ a few years later, to put that into perspective.

At first, I thought I could just use generic ones and not use the Supermicro rails at all. That may sound odd, but I still have some Inter-Tech branded ones laying around from their fuckup with the 4098-1 case that didn’t fit 3.5″ bays when the 5.25″ were occupied. They do fit the (new) rack nicely, while the Supermicro rails do not:

While being a thoughtful quality-of-life feature for the poor soul that needs to mount the rack rails, this actually prevents them from being installed into my rack. I use standard Adam Hall 61552 rail posts and the springs of the Supermicro part are just too long to fit inside the U-shape of the post:

They do on the other side where I reverse-mounted the post on purpose, but for the front – no way. I actually cannot remember if it is possible to just remove these plastic helpers on both sides without further modification – I know that it can be done on one side, but that might be the wrong one. These Supermicro parts are keyed for left and right. Chenbro rails are symmetrical so they can be mounted upside down without a problem – not sure if that’s the same for the Supermicro parts. At least you would know they are upside down with the enlarged part near the ends.

When I figured that out, I had already switched cases once. I went with the old one initially due to the non-expander backplane that shouldn’t cause problems when running SATA drives. As soon as I found out that I could use the newer and also less damaged case, I moved hardware into that one. But that one has the newer, narrow mounting hook arrangement. Bummer – went back to the older one with larger distance between the mounting hooks to accommodate the generic sliding rail. I think two screw holes can be reused, and I cut in two more (M4) per side for some extra strength.

(photo angle strategically chosen – yes, I know, there has been liquid damage, no, it cannot be cleaned up much better than that. I never said it was an indoors dumpster.)

Well, turns out – it doesn’t fit the rack once mounted onto the case. Basically all Supermicro cases come in “437mm” width (more like 440 in reality), while Chenbro and others usually range from 430 to 432mm. With a usable space of 451mm between the rack posts, it’s not difficult to imagine that generic mounting equipment that takes space on both the case and the rail post does not fit Supermicro gear. Four times a few millimeters just make it too narrow to fit.

Pleased to meet the twins from Austin Powers:

Doesn’t fit because I just assumed all 19″ gear is the same – Fook Mi.
Doesn’t fit because of design choices – Fook Yu, Supermicro.

Aaand, going back to the new case. Get the rails, make it fit. At all costs. Unfortunately I don’t have many photos of that, as it was a lot of back and forth, trying things, looking for a solution that works. I can show the final mounting in the rack as it is today:

Outer part (lowest chassis):

You can see four M4 nuts where there have been 8 rivets. Four of them can be drilled out directly, while the other four are hidden from the inner rail. You can remove them from the other side, which is a pain in the ass. And you still need to remove the remains of the rivets, so nothing is gained. I found that removal of the end caps (the two metal stoppers that prevent rear-extension) is necessary, and coincidentally, it is also much easier to separate everything that way. Once they are removed, the four remaining rivets can easily be drilled out and removed as well.

I could drill two more holes in the back to stabilize the thing even more, but I cannot be bothered. The two holes in the front could be used in theory, but the rail is extended very much to the back to do that. There’s a high risk of the ball bearings falling to the ground – nothing that would damage the system permanently, but a real PITA to get them back in position. So I would need to drill holes in front as well – and as I said, I cannot be bothered. Works for me.

Inner part:

I know, far too few cables for a proper rack. From the inner moving rail you can see a piece that has been cut out with the Dremel. I tried that to move back the thing a bit more, but there’s no way around removal the end stoppers. So – don’t do that. This mid-stopper does stop the moving inner bearings as well, so losing that isn’t the best idea. Also you can see that the second pair of screws doesn’t actually hold together all three metal parts, but just two of them. Works, but if you do something similar, please move over a bit and drill through all three of them like I did later on the other rail. The individual parts can go nowhere once mounted in the rack, but its nicer and more secure that way.

Also, it is possible to use countersunk screws as the rails allow for like two to three millimeters of height in those two spots. No need to use a rivet gun or something fancy. Just countersink the holes a little.

Last thing on the rails: When used with broad washers, they can get in the way. So I filed them down on one side, otherwise the fixed rail does a slight U shape. Not too bad of an idea to prevent sliding it back out after the end stoppers are removed, but certainly not designed to do that.

With that tiny bit of modification and the loss of like three Saturdays – just click in the inner rails to the case:

Move it in place, slide it in – and enjoy.

Never take it out again :twisted:

(I should replace the rusty screws in front, now that I saw it on the picture!)

So this is the current setup – the 4U Chenbro that originally housed both server and desktop is now freed of all the server stuff, and the ZFS server is sitting on the bottom of the rack, doing nothing until the SFX power supply arrives that Hermes Germany isn’t able to locate since about two weeks. The 2U case above is home to an socket 462 retro system that proved too weak for VHS recordings, more on that in a future post. And all above that is now the APC UPS – it’s heavy, I know, but the place on the very bottom of the rack turned out to be even less practical. Besides, above the table top sits another heavy weight – my 40kg Samsung printer ;) It won’t topple, the desk has another two-post rack on the other side, weighted down with another 30kg of audio equipment. That thing is rigid, don’t worry..

Guess that’s it for today. Unexpected hardware delivery with some problems fitting in – just use a bigger hammer to make it fit. Or use some brains and almost your entire tool box to make it look less botchy. Or spend some money to buy original parts. Or toss both 800€ cases entirely and buy a Chenbro or Norco. Your choice.


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