Storage Solutions Optimal fan placement for 6 HDD DL rig

[Sei]

I've finally attached all HDDs to my DL rig but now am facing another issue - heat.

With 6 HDDs in my system, it gets quite hot. The HDD temperatures touch anywhere between 42-50 deg C as compared to my main system where it stays a cool 35-37 deg C.

Here's what it looks like -

There is space for 3 fans - 2 x 120 MM and 1 x 80 MM

I've purchased 2 fans -

1. BitFenix Spectre Black 120 mm (43.5 CFM)
2. Deepcool Wind Blade 80 MM (21.5 CFM)

Now, my questions are as follows -

Which is the 3rd 120 MM fan that I should pickup and from where? Online would be preferable.

Also, what would be the ideal way to place the fans for maximum cooling? I read a bit about positive and negative air pressure and wanted to know which would be best for this particular situation.

@Gannu, @ALPHA17, @cranky Thanks in advance!

 

[cranky]

Net positive pressure has higher temperatures than negative pressure. Positiv pressure requires filters, negative pressure don't bother as dust seeps in through every millimeter gap in the case.

If you clean regularly negative pressure is the way to go if this is to be dumped in a loft put lots of intakes and put filters on them )you can make filters out of old mosquito nets, speaker grille cloth, Netlon plastic netting, just cut to shape.

To your temps. You can expect a well-ventilated drive to be about 10 degrees above ambient when operating, and 7-8 degrees idling. In summer you will get temps in the 40s, unavoidable though it seems high now. Of my 6 drives 3 do not have a fan on them at all but they are Green drives and used as data mirrors (not RAID1) so they hardly ever operate at all, only when the mirroring is being done. This leads to their temps never exceeding the mid-30s (basically room temperature) before turning off again.

I have a single 120 up front, a single 120 in the back, all cabinet holes sealed off and my WD Black drive is in the lowish 40s but I know will be 48+ during summer. Nothing I can do about it but as long as it's constant it's not a big issue. Drives have bigger problems with power cycling than high temps. The other three drives similarly stay turned off till I use them for data access and then get switched off. IME I've never seen these drives cross 40 degrees at any point in time.

I would suggest examining your power saving strategies, both in BIOS and the OS. Try turning drives off when not is use after 5 minutes. Be aware that unless you watercool or duct your AC to the computer, you will always be limitied to about 10 degrees above ambient no matter how much airflow you have.

Drive spacing you have used is very luxurious but not turbulent enough. Put the drives closer together and use a high flow fan in front. This actually cools better than your present arrangement.

 

[6pack]

my advice is to remove the 80mm side fan and plug that hole. Looking at its placement, it would actually circulate hot air coming from the hdd's and cpu all inside the cabinet towards the bottom. Then you be in a situation where you have hot air circulating in the lower part of your cabby. The bottom part of your cabby below the back fan looks large enough to hold the 80mm fan. You could improvise and make the 80mm fan as extra exhaust just a few inches below the 120mm exhaust fan. You will need to tidy up that space a bit though so that the sata cables dont go insude the fan.