[ukbjorn20001]

Hi all,


I spent all of last night reading threads on the NORCO RPC-4220 builds. Very impressed...


I too joined the clan and purchased one a couple of weeks ago to build a custom WHS to replace 4 external arrays I currently have tethered to a VMC machine in a RAID 0 configuration.


So far last night I learned that my PSU is WAY under speced, and I gather to run all 20 drives I will need at least a single rail 850W PSU, am I correct ?


My big problem so far, my unit is one of the new ones with the mini SAS backplane. On the suggestion of a thread I read, I purchased 3-Ware's reverse breakout SAS to SATA cables. Plugged one in last night and connected all 5 SATA ends to my mobo. Problem is that it would only see the drive in slot one. I know I am going to have to buy some extra PCI cards to get more SATA connections (cheaper than mini SAS cards), but is my problem that my mobo does not recognize SAS ? Please help.....


Bjorn

 

[mexicanmike03]

What mobo do you have? Since the mobo is accepting a sata connection, SAS compatibility I dont think is the problem. I know its a silly question, but how are the drives in? The top row will be controlled by one backplane, so drives should be arranged in the slots horizontally if there is only one sas breakout connected. List your parts, it will be easier for people to help you. Also I think there are a few people using a 750w power supply, at least I hope soo... cause thats what I will have and if it doesnt support all 20 drives im screwed, LOL.

 

[WolfDV]

on my norco 4020 build; i'm using 13 drives atm; along with the rest of the components. currently running on a corsair 620HX;


so far no issues (even during intensive parity checks on unraid)


eventually in the future if the need/price is right, may upgrade to a 850HX .. i'm in no hurry though

 

[Piglover]

Re: power supply.


Your only problem is on spin-up. Typical modern 3.5" drives peak about about 2.5amps on the 12v rail to spin the platters. They hit this peak for just a few seconds and then ramp down quickly. Your 20 drives will draw up to 600watts on the 12v rail, but only if all of the drives happen to peak at exactly the same time. You can avoid this completely if you get a controller card that supports staggered spin-up.


Under heavy load (rapid seeks) a non-green drive draws only 0.6amps. Assuming you managed to get all 20 drives seeking at the same time your nominal operating load should never exceed 144watts. Add another 150 or so for the rest of the system and you can easily deal with a smallish power supply. There is absolutely no need for the 800watt single rail PSU.