[SOLVED] New PSU for Norco Rack server with 24 Sata Drives? (Having issue with old one)

[gwpt]

Hi,

I have the following setup:
Norco RPC-4224 Rackmount Server Chassis
Zippy 800W EPS12V Dual Redundant Power Supply (MRG-5800-4V)
Gigabyte GA-Z77X-UD5H with i7 CPU + 32GB RAM
Adaptec 72405 Raid
20 x SATA Drives (Mostly Seagate Ironwolf 8TB+)

Since adding about the 18th drive and seems worse now that I have 20 drives, I get drives randomly disconnecting. By Shuffling them around I seem to have found a usable config. But I occasionally still get one drop.
The actual error from the raid controller is e.g.:

Physical drive removed: controller: 1 ( Adaptec ASR72405 #4B261373352 Physical Slot: 16 ), channel: 0, deviceID: 18, WWN: 5000C500C03BD585, vendor: ATA, model: ST8000VN004-2M21, S/N: WKD0107D, firmware level: SC60.

This can happen randomly, not just at boot time when the drives are spinning up.
What makes me suspect it is power, is that if I turn off 1 of the 2 redundant power supplies (On the zippy it has two power input, I disconnect one), then it always happens, and will drop about 2-3 drives during boot up.

So. my suspicion is that the PSU is defective or can't deal with the load and that 20 is about it's limit. (Even though at a max of 2A per drive, that would still seem well within the limits of an 800w supply..)
But I have no way of testing it that I know of...
I would like to fill the rack complete with 24 drives.

Current plan is to replace the Zippy with a Corsair RMx series PSU.

Does this seem like a reasonable plan? If so what wattage?
The RM750x, RM850x or the RM1000x?
https://www.corsair.com/us/en/Categ...ply-Units-Advanced/RMx-Series/p/CP-9020094-NA

Thanks

 

[popatim]

Have you enabled staggered spin-up in the Adaptec? It should help with that issue by only spinning up a handful of drives at a time. Spinning them up to speed takes the most power. Once they reach speed, they typically consume 4-8 w