Powering hard drives.

[Zerosum]

My question is how to go about figuring what's needed from a PSU for hard drives? I know boot time is the largest draw so I'm guessing that's what I really need. That spike during boot time.

In my case, most of the hardware is kinda modest. Normal supermicro board, q6600 (no OC), onboard video, 2 RAID-ish cards. But the kicker is, I need to power a ton of hard drives. Close to 60 2TB drives.

You can guess it's gonna be some major mega-file server. Most of the drives are 'Green'. Drives will be on all the time running zfs/raid, so they'll probably be spinning. Boot up I will try to stagger them so spinup doesn't kill everything.

What kind of PSU should I be aiming for? This particular machine is for my home use but since I don't have to deal with an electric bill, being efficient isn't a high concern.

 

[NobleX13]

Lord almighty, that is a ton of hard drives! I'm still looking for exact figures, but you can ballpark about 15-20 watts per drive.

 

[Zerosum]

Is that 15-20w for power-on/spin-up? It couldn't be that high for 'normal' use right?

I really should take pictures for the Data Storage forums. I have a wall of brand new hard drives on my desk but can't use til I get the final card needed to attach to the machine.

 

[Zero82z]

Is that 15-20w for power-on/spin-up? It couldn't be that high for 'normal' use right?

Correct.

For a setup like this, I would recommend a 1kW PSU minimum, but preferably a 1200W PSU. I assume the cards you're using have support for staggered spin up?

 

[Zerosum]

Correct.

For a setup like this, I would recommend a 1kW PSU minimum, but preferably a 1200W PSU. I assume the cards you're using have support for staggered spin up?

I honestly don't know (yet).

My current setup is a SuperMicro AOC-USAS-L8i HBA which will be attached to the HP SAS expander card. And it's from there that the connections will be made to the drives. Unfortunately, I'm still waiting for my HP SAS card to arrive sometime next week so I haven't plugged things in yet. I picked up that card from another [H] member and that's the time that was provided.

Luckily, I'm getting a replacement HBA card (Areca 1680i) to replace that SM AOC-USAS HBA next week as well. I'm pretty sure the areca will support staggered spin up but I don't know if that will remain true through the HP SAS.

Worse case scenario would be I manually (slowly) power up this monster. It'll be on a UPS and with it being just a file server it should never need to powered off anyways so that's not a big deal. Especially since this is for my personal use at home so nothing is business critical if I need to bring system down. I currently have the system on a corsair 850. I'll need to re-evaluate my power if 1k+ is recommended.

 

[Dangman]

On average, a HDD will take up to 2A or 24W on the +12V rail on startup. So if none of those cards support staggered spinup, you might be looking at a 1500W PSU for the 60 hard drives alone for startup.

So yeah, before you start attaching more drives, make absolutely sure that you can get staggered spinup. Otherwise, you're looking at 2 or even 3 PSUs.

 

[BillR]

On average, a HDD will take up to 2A or 24W on the +12V rail on startup. So if none of those cards support staggered spinup, you might be looking at a 1500W PSU for the 60 hard drives alone for startup.

So yeah, before you start attaching more drives, make absolutely sure that you can get staggered spinup. Otherwise, you're looking at 2 or even 3 PSUs.

Call me crazy but I’d feel more comfortable with a separate PSU just for the drives.

I wouldn’t want to take the chance of other transient loads, like the tons of fans you need to keep 60 drives cool, interfering with the boot and drive sync process. The second PSU would be a minor investment compared to the possible data loss.