So...how many 2.5" disks can you put in a Chenbro NR40700?

[nexox]

I can't help but think those fans would be a lot more efficient with some kind of cowling, even just partially with curved triangles coming in from the sides between fans and maybe some large fillets in the corners.

 

[kapone]

I can't help but think those fans would be a lot more efficient with some kind of cowling, even just partially with curved triangles coming in from the sides between fans and maybe some large fillets in the corners.

I thought about that, but the spacing is quite tight now, there's literally ~0.3" of space between fans and the box walls (vertical side). When I was doing temporary testing, it did look like the fans work just fine with no cowling (remember these are ceiling fans...). I think it might be the curvature of the fan blades and the fact they have ~5" of space to draw air from. On a ceiling, it'd be even less.

 

[nexox]

Right, a ceiling fan isn't going for any static pressure either, not sure what your setup will need, but allowing (relatively) high pressure air to spill over the blade tips to the low pressure side of the blades won't be great for forcing airflow through restrictions. Come to think of it the blade tips passing each other might also make some extra noise too, depends on rotation speed.

 

[kapone]

Right, a ceiling fan isn't going for any static pressure either, not sure what your setup will need, but allowing (relatively) high pressure air to spill over the blade tips to the low pressure side of the blades won't be great for forcing airflow through restrictions. Come to think of it the blade tips passing each other might also make some extra noise too, depends on rotation speed.

That certainly is a concern, and I won't know till I finish the frames and mount them. But yeah, static pressure is not needed in this case, just airflow. All of the compute sleds (They're all open frame, with no chassis) have active CPU coolers on them (Dell...) and are spaced 3U apart.

Only the low power cluster is spaced 1U apart and those boards do have passive heatsinks on the CPUs, but these really are low powered (ranging from 35-65w CPUs) and will never really be working too hard.

The low power cluster is really just a playground for testing stuff.

 

[kapone]

Mounted the first frame with 3x fans. *WHEW* No turbulence issues, the airflow is fantastic, and while not exactly silent (there's a boatload of airflow, most of the sound is just air being beaten), it's very quiet. From more than 2ft away, there's no issues with sound.

My dimensions for the frame were just a hair off, but nothing that was a deal beaker.



Now build the other one...gah! But, I'm stoked! This is rack level cooling and it seems to be working great from a physical standpoint. Once the compute sleds are in, will take measurements before/after.

 

[kapone]

Getting there...The second box frame with 3x fans is in, the "big" compute nodes are in (dual CPU, 256 to 512GB RAM), the two "workstations" that can handle multiple GPUs are in...just gotta finish the "small" nodes cluster.

In total:

- 9x big compute nodes
- 7x small compute nodes
- 2x GPU workstations.



p.s. Yes, the space is messy right now, it'll get cleaned up.

 

[kapone]

btw...the HP PDBs use 16 gauge wires...they're thick...and stiff...and a pain in the rear to work with. And I had to repin ~14 PDBs...my hands are sore!