[Request for Ideas] SuperMicro SC836 PCI Air Flow Management

svtkobra7

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Jan 2, 2017
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I purchased 2 x Sun Flash Accelerator F40 recently, and while they don't arrive until Thursday (and I don't even have a baseline yet), I'd be willing to wager a few bucks that I may need to manage air flow for the PCIe cards. I suggest that as: (a) others have noted they run very hot, (b) Oracle even recommends airflow of 200 LFM, (c) back of the envelope calcs don't put me there, and (d) looking to personal past experience as precedent, if there there is any chance I will have a thermal issue, I will.

Here is what today's config looks like:
Sun is hot.jpg
In this mock up, I believe the ideal placement is a fan perpendicular to the PCIe slots (beige rectangle), which aligns with the existing air flow schema: Chassis Front => Around HDDs / Through Backplane => [CHASSIS MIDDLE FANS] => Over Motherboard => [CPU FANS] => [EXHAUST FANS] => Chassis Rear. Of note, the chassis is vertically wall mounted, with the chassis front facing the floor and chassis rear facing the ceiling, and that orientation aligns with air flow in the closet (too shallow to mount horizontally) where dense, cool air is sucked in under the door (negative pressure created) and expelled by a ceiling fan. Warm air exiting the chassis with some velocity + convection + exhaust fan = thermal scenario managed to my liking with HDD temps @ 40° max, with a script monitoring those temps and adjusting fan modes accordingly (usually the Standard profile is engaged, which is quiet enough for my liking considering I insulated the closet with Roxul).

Notes: [1] Nevermind the fact that the existing card is in the worst slot for airflow [2] Red rectangles represent possible F40 placement.

HW Config:
Now that I've needlessly wasted your time with that monologue, I'd like to ask for your ideas on how to get a fan in there / otherwise manage air flow. I did put some effort into the server and closet, so I'd like to stay away from a zip tie solution. Heck even this Adjustable Magnetic Fan Snake Stand doesn't really seem fitting. ;)

I know there are a number of other options: (a) Brackets that blow air down on the cards from a fan on top, (c) Brackets that blow air to the side, (d) Brackets that push air out the PCIe bracket, etc. but I haven't found exactly the right solution and would like to crowd source for options.
I look forward to your feedback and of course will only pursue air flow management AFTER I have a baseline, I'm just being my usual over-analytical self in advance. Thanks! :)
 

svtkobra7

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Jan 2, 2017
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Thanks for your reply. One of those is my 2nd choice and (w/ slight mod) allows me to blow air out the rear of the chassis. As does another, but at the cost of a PCI slot.

How big of a deal do you think direction of air flow is as I consider options? When I was initially reigning in HDD temps, it seemed like every nuance mattered. Different ball game here and am I worthlesssly overanalyzing?

Sent from my SM-G950U1 using Tapatalk
 

svtkobra7

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Jan 2, 2017
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With 2u heatsinks you could use the supermicro shroud and adjust it to guide the air from the mid wall fans to the add on cards. (See my post here: Supermicro 846 cooling of PCI-E HBA controllers?).

But with the tower coolers I would look for fans that you can mount in a pci slot.
I don't see how it could be adjusted to fit? It won't extend that far over and it won't fit on top of those Noctuas (they are 3U). Maybe I misunderstand?

I do like the idea: it increase velocity due to reduced air flow path.

Wouldn't it be kinda cool if my fan script triggered a shot of N20 to be dispersed when temp hit the next threshold (instead of ratcheting up RPMs). Fast and the Furious in the DataCenter. OK, really bad joke.
 

cheezehead

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Sep 23, 2012
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For the normal fans behind the backplane, they do make a couple different models with different amounts of noise/cfm ratings...could go with a higher cfm model. I've seen some storage vendors modify the SC836 chassis and place another 60mm high cfm fan where the blue plastic is on your chassis for cooling high temp raid controllers.
 

Rand__

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Mar 6, 2014
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Ah - makes sense- I remember some ages old SCSI HBAs being that long. Thanks
 

Terry Kennedy

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Jun 25, 2015
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www.glaver.org
I've seen some storage vendors modify the SC836 chassis and place another 60mm high cfm fan where the blue plastic is on your chassis for cooling high temp raid controllers.
That's actually an option (4-fan backplane tray) from Supermicro. It is used on the HA (High Availability) versions of the SC836. Those also include a PDB that supports either 3 power supplies or 2 supplies + BBU unit. The fans used are:
Supermicro BOM said:
FAN-0140L4 4 80x80x38 mm, 9.5K RPM, SC835B Middle Cooling Fan
instead of:
FAN-0126L4 3 80x80x38 mm 7K RPM Chassis Middle Fan w/ Housing
I have no idea how you'd go about getting the fan tray for those as a separate item from Supermicro, though - it seems to be one of those things (like the oddball metric/inch standoffs used for old CPUs or the JBOD board) that doesn't have a part number and that Supermicro won't sell / send out for free.