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PSU Wattage Advice

indivision

Senior Member
Joined
Jan 4, 2013
Messages
405
I have a server containing 12 spinning hard drives, 2 NVME drives, 1 SSD.

Supermicro X11SCH-LN4F MB. Xeon E-2136. LSI SAS9211-8I. 32GB ECC. Around 5-6 fans IIRC.

All of this is running on 650w currently.

If I am calculating correctly according to recommendations, this is just enough power. But, the margin is small and I'm not sure what being short on power would look like. Would it be random, unpredictable errors? Fail at boot?

My concern has become greater now that I've had a relatively new (6 months old) WD Red drive fail SMART tests. Is it possible that being short on power caused this?

Interested in experienced advice on if I should get a bigger PSU? If so, what would be sufficient? I don't anticipate adding more than potentially 2-3 more drives max, if any. But, I would like to eventually add a GPU to use for passthrough with SCALE when it gets a little further along in development. I'm assuming that is probably a big power draw.

Thank you in advance for any insight you can give.
 

sretalla

Wizened Sage
Joined
Jan 1, 2016
Messages
4,289
what being short on power would look like. Would it be random, unpredictable errors? Fail at boot?
A little of both... Boot time is perhaps the most probable as all drives are spinning up from stopped, which is the highest power draw.

You may see some strange behavior that doesn't exactly manifest as a clear stop of any of the disks during heavy IO load (like a scrub/resilver or long SMART tests).

My concern has become greater now that I've had a relatively new (6 months old) WD Red drive fail SMART tests. Is it possible that being short on power caused this?
What kind of failures are you talking about? tests failing to complete? (yes, this might happen due to power issues) read/write/CRC errors (also possible, but I would say less likely)

Interested in experienced advice on if I should get a bigger PSU? If so, what would be sufficient? I don't anticipate adding more than potentially 2-3 more drives max, if any. But, I would like to eventually add a GPU to use for passthrough with SCALE when it gets a little further along in development. I'm assuming that is probably a big power draw.
Generally, having a power supply with a fair amount of headroom is a good idea as it's usually able to run without needing a fan and you don't risk device brownouts at heavy load.

A power supply only draws the current needed by the computer, so having a bigger power supply doesn't cost you more power to run the same computer (and if you get a very efficient one, maybe less than a smaller, less efficient one). Investing in a gold or platinum supply is wise.

I think an 850 or 1000 Watt supply would probably be suitable for your use case.

In case it helps, I'm running 24 HDDs, 4 SSDs and 2 NVME drives in my primary storage on a 1200 Watt unit, so clearly with half the disks, you could get away with a smaller one.
 

indivision

Senior Member
Joined
Jan 4, 2013
Messages
405
Thank you. This is helpful info.

What kind of failures are you talking about? tests failing to complete? (yes, this might happen due to power issues) read/write/CRC errors (also possible, but I would say less likely)
One drive started showing failed SMART tests. I don't see any indication that the SMART test isn't completing. It's just showing some problem with the drive. And only that drive. So, I think this most likely points to a bad drive. But, maybe power shortages contributed to it failing early?

Investing in a gold or platinum supply is wise.
The current one is a Corsair Gold. But, I think I'm going to need larger no matter what with the GPU. So, I'm going to shop for a 1000w Gold.
 

indivision

Senior Member
Joined
Jan 4, 2013
Messages
405
Thank you. I had used that guide to plan the current PSU. But, I ended up adding more drives than originally planned. It's ok. I'll just sell the 650w and pick up a 1000w. Good news is that pricing is pretty good on PSUs right now.

Now I need to learn what a good GPU is for pass-through use. :)
 
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