Topic: Request for Discussion: proposal for standard modular rack miner - page 6. (Read 9613 times)

Yeah I was mostly referring to the heatsink dimensions, and the double sided nature of the boards. 

I should have a couple of good visuals done up by tomorrow as well

Actually, a lot of the information in the first post is no longer really relevant after changing board dimensions. Board and sink mounting still applies, but PSU placement and most everything else related to power is changed. I guess at some point I should write up a complete revision with updates from the last few days' discussions and link to it in the first post. Maybe I'll have time to draw some diagrams too.

Chig - What package do you use for modeling? Do you want/need any source files from my model?

NWF/Sidehack - I didn't realize that shelf supports were standard.  I figured the tolerance on the height was just to play it safe.  Good to know as that frees things up a bit.

Regarding the depth I think I could make a 20 work, but it might not be optimal in terms of flowpath.  I just realized how much info I glossed over in your original post, I get to eager sometimes.  I have some actual work I need to do this afternoon but tonight I'm going to try and rework my first draft to really align with your first post and get the heatsinks/board mounting right. 

If I were using DPS2K I'd wire them up externally, probably with dedicated fans.

DPS1200 measures are already in here somewhere, as well as I think the Emersons and DPS1200TBA (platinum-rated).

Witrebel, no you've got the back panel right. I meant a solid sheet with circles cut out for fans and then an external wire grille per fan. That should be structural enough for things to be comfortable stacked and if chig wanted to run waterblocks he could pull the rear fans and use the space to run his tubes out without having to take off the back panel (which would structurally weaken).
If we wanted airflow for something like S5 that really doesn't work well without both sides cooled, front fans would be necessary in this case. Yes, taking cold in the front and blowing hot out the back is the standard.

It might just be me but I'd like to limit case depth to about 20 inches. This wouldn't affect most rack installs (where things can be substantially deeper) but a bigger box would cost more to ship and be more cumbersome to handle - and for the home miners we're considering secondarily, bigger isn't always better.

Also, being as the box is probably going to weigh between 40 and 50 pounds, I'm not sure I'd recommend mounting it just by ears. That seems kinda dangerous. From the start we were figuring on shorting the case height by a couple millimeters to allow for rack shelving.

Only very light equipment is held only by the ears. Anything over a pound or 2 and deeper than a few inches MUST be supported by a sheet metal shelf and the ears are only to hold it in place. 1 shelf - 1 piece of gear. eg http://www.budind.com/view/Rack+Equipment/Server+Rack+Open+Rack+Assembly or http://www.budind.com/view/Rack+Equipment/Four+Post+Double+Rack with the shelves in it. While yes you could stack a couple miners per-shelf if soon becomes a pain when the one on the bottom has to be pulled...

Having plumbing + Fans on the backplate would be amazing, as the S5 is known for its need of having fans anyways because a lot of heat is dissipated through the ground plane of the chips

Sidehack, do you think you can hand me the DPS1200 or the DPS2K measures so i can take Witrebel's design and rapidly iterate over it to find ways to fit them?

The only problem i see with the DPS2K is the lateral cooling they need, how would you handle that on this current design?

Yeah I realized today that depth wise I'm not really rendering to your spec.  I'll get that tweaked this evening probably.

regarding the fans/grills, I assume by rear panel you refer to is the panel that I currently show 3 fans on, and you are saying that instead of a panel with 3 holes, you envision an open wire mesh. It seemed like there was some concern that something like that ingesting hot air from the isle through the wire mesh due to the negative pressure in a strictly pull fan configuration.  If you want it like that then I think you may need the front fans after all.

As I have it laid out, you would intake through what I called the "front" which would be your cold isle, and exhaust through the rear to the hot isle.  Is this the "standard" flowpath that you guys run in your farms?  Just wanna make sure I have it straight it my head.

Also, for the sake of the discussion, are you okay with going deeper so long as it doesn't involve any more than the standard S1 ~10 card in terms of "hash cooling flowpath".

If we could go to say 24" deep max, I could probably get something pretty slick laid out.   The nice thing is that having the PSU's at the front of the miner reduces the bending moment on the rack mount ears that you would get if the weight was all the way in the back.  So it could probably be done with just a 2 post rack.  Watercooling might get heavy but thats up to the end user to figure out.

Actually, the more space left between the rear of the board and the back panel, the easier it'll be to handle plumbing from waterblocks. 1" from board to fan and 1.5" fan makes 2.5 inches; is that enough room to be comfortable? Another depth consideration is PSU length, which the DPS1200 is about 8 inches but those Emersons are closer to a foot. If there's gonna be backplane for them to socket into, and also room for internal cabling, that's probably a minimum if 18" case depth.

I'd be a little leery of stacking PSUs in front of the hashboards. It might work for DPS2K (and that's a nifty setup; most of my big DPS2K installs here at the shop powered Tubes and Prismas which didn't really have the cooling overhead to add that kind of additional heat and airway restrictions) since air'd blow right through but any solid supply like is more common would block a lot of air. I mean there's probably a way to do it that isn't entirely stupid, maybe mounting the front fans internally and behind the PSUs, but then you need more gap for air to get around them and with more than one PSU on top of another you're really eating into your intake path.

It'd be really nice to fit an eighth blade in there, but I'm not sure if there's a better way to mount PSUs (without going full external or significantly changing case dimensions) that gives the heatsink space and also adequate airflow.

^ ^ fan type and space between them and the sinks should be perfect  

Thinkin' about it, the boards are more like 10 inches long. That's what I get for trying to remember stuff after being awake for 21 hours.

The original spec had space for nice 38mm-deep fans, and minimum one inch between fan and either leading or tailing edge of the PCB.

I also figured the rear panel for fans would best be done with the entire fan area knocked out and use a wire grille. If nothing else, those penetrations could also be used to route plumbing for waterblocks without having to make the entire back panel removable (which could cause problems for other things, like structural strength if machines are stacked).

Hopefully I can get a thermal simulation package running soon and put some of these ideas through the paces.  I'll play around with front mounting the PSU from a layout perspective just to see what can be accomplished. 

Does anyone have any experience with design for manufacture?  Specifically what are the cheapest construction methods?  I ask because if it doesn't add too much additional cost of manufacture, I think this may benefit from a deeper case, same size hash cards, and some dedicated flow straightening vanes/features.  Im thinking something like the struts, where they can just be simple stamped sheet metal pieces, tack welded or riveted to the case in strategic locations to optimize the flow path. 

heh heh heh
Works very well though and is same depth as the s4 under them. https://i.imgur.com/aTkVsGE.jpg
Was tossing that out there for consideration

One thousand sidehacks weeped with that pic

So far looking good. For best airflow 2 things to keep in mine:
With 1-side fans the back of the case must be louvered vs just punched or preferably wide open and fan sized w/fan grills for if folks want to add outside fans in the back. Done to minimize dead metal in the way.

Preferably should have at least 1/2" between the fans and first edges of the heatsinks and/or use fans that have flow straightening built in like some of the nice thick Delta fans. This gives the air a chance to start straightening out and greatly reduces front edge turbulence. Also gives a significant reduction in noise by reducing the siren effect.

On longer case, I was more thinking about having the PSU bay possibly in front of the cards to fit in another card or 2 width wise vs cooking cards in a back row. Ja it adds heat to the hashboad airstream but works fine in an open air proof-of-concept. I do it in my farm to eliminate needing fans on some of my IBM 2kw supplies. https://i.imgur.com/XRlk5Tq.jpg btw that area often runs ambient up to 93F, and those psu's/miners still happy.

The last render I posted had the S1 cards at 12", so you get alot of space freed up if they are really 9" cards. 

Furthermore, I *think* sidehacks issue with going deeper isn't as much about case dimensions as it is about how long the hashing cards are.  That is part of why I want to get some sort of simulation running that accounts for both the flowpath and the thermal loading. Alas my current cad seat does not have the right simulation package and I can't get anything new hooked up until I'm off this damn boat.  Simulations may be a bit premature at this point anyways, but I wanted to get a general objective idea of pro's and con's to some of these points that get argued like negative vs positive pressure, push-pull vs pull, flowpath length, etc. 

The original spec is 15" between the fans, which puts the case at more like 18" length. This can be adjusted a bit since the blades are now only 9" long instead of about 12" but I wouldn't be surprised to see the final case come in longer than 15 inches, especially once dimensions get ironed out for PSU requirements.

If the internals are stacked closely together/high density then adequate cooling can be achieved with high static pressure fans instead of high flow (cfm) fans.... particularly in a push/pull configuration....I have used this type of setup on miners before and achieved better cooling than stock miners...I always swap out the fans on miners as it seems they always seem to choose poorly (or maybe it is to save money).

 S1 size cards are quite a bit taller than PCI-E cards, though a few GPU cards have fans that stick up a fair bit above the top of the board.
 S1 cards are also longer than most PCI-E cards.
 You also have a case that is almost TRIPLE the length that sidehack is trying to fit everything into. Personally, I think he should go a little longer on the case, 15" is EXTREMELY SHORT for any rackmount case and even a couple of inches of extra length would help a lot on fitting stuff in and making the air flow smoother.


 I agree that 2 cards in a row = VERY BAD IDEA, especially if we're talking 300 watts PER CARD. Rear cards are gonna overheat BADLY unless you get very fancy with air ducts and such, and then you reduce the cooling to everything.

What I would do is not have nylon rails because, as I've mentioned two or three times so far, they're pretty crappy structurally and a card with 2lb heatsink attached is going to get destroyed in shipping. It's better to secure the 2lb metal block to something structural and secure the 4oz fiberglass board to the metal block.

Another reason to do that is, if we stick with S1-style boards, the board and heatsink are the same length so there's no board edge for rails to grip anyway. The heatsinks on an S1 are less than 50mm wide. Take a look at Witrebel's case render, and you get pretty much exactly the geometry I'm envisioning for 7 300W blades and 3 redundant 1200W PSUs in a 4U case with built-in controller.

I think a good way to address PSU flexibility is to have basically a terminal block that all the 6-pin cabling to the cards comes back to. Someone could cook up PSU backplanes that link 2 or 3 supplies together load-balanced and route power up to the terminal block. If someone didn't want internal supplies, a $10 wiring harness with snap-in jacks at the rear of the case connects to the terminal block. That maintains modularity which reduces the overall cost and limits what has to be replaced when going from external to internal, or from one type of internal to another.

I also would not put rows of cards in a super-deep case because, well, anyone with Spondoolies gear can figure out why. The hot air from the front cards bakes the rear cards and they don't cool worth a hoot. Considering each board could be pushing out 300W, do you really want 2KW of heat blowing directly into another stack of things generating 2KW of heat?

I know there's been a lot of words said so far, but when a point that's been addressed twice already gets brought back up (with no new arguments in favor) it's a bit frustrating.

and here im playing with a HP server, 10 SAS HDDs, 2x Xeon CPUs, room for 6PCIex8/16 cards, and 2x 800W PSUs neatly in 2U, and people are having trouble understanding 7/8 cards +HS and even just 1PSU in 4U?

you can fit a full sized PC in 4U..
in a full length PC, you probably be able to have 2, maybe 3 cards length ways, but thats not the issue..

A S1 board is about 155 mm high, 4U rack unit is 177 mm high.
i cannot find the width of the heatsinks for the antminers so i'll use the dimensions of the 120mm fan, and the 2 sinks facing it, so each heatsink is approx 60mm, but the Rack unit is 465 mm in width so thats ~7 cards with sinks and breathing room.

Adding a single atx PSU, thats 90mm less space, so about 2 cards less.
these server cases are about 1000mm long each antminer unit is 300mm long, with fan.

so you can fit rows of boards in, one row will be 2 less for a single PSU, but thats 7 cards x 2 rows, plus another 5 more cards next to the PSU.
but are we looking for a backplane that sits at the base of the case and have multiple cards sitting side by side and layered?

my idea on how I would do a case'n'controller:

open face, with blank brackets thats 40mm long 170mm high (4U case) you could fit 11 cards right across the face, each card slot has nylon rails, backplane with power connection and usb. behind the backplane is HP style redundant PSUs. next to them, $50 atom itx motherboard, with whatever OS you want. Why ITX motherboard? im over trying to configure RPis or tl-wr702n's.