• Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
    Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.

Power for 24 HDs ..

N

nefarious986

n00b
Joined
May 6, 2008
Messages
19
I m planning a build for a 24 disk raid, most likely using 750GB seagate sata ( cant afford the new WD green HDs =T )..

Anyways, would a good 1000W PSU be able to support that ?

Does HD draw from the 12V rail or 5v rail ?

Thanks
 
nefarious986 said:
I m planning a build for a 24 disk raid, most likely using 750GB seagate sata ( cant afford the new WD green HDs =T )..

Anyways, would a good 1000W PSU be able to support that ?
Click to expand...

With staggered spin up probably. Good luck with the 24 connectors though since there are very few that have them (Galaxy).

Does HD draw from the 12V rail or 5v rail ?
Click to expand...

Both.
 
Should be about 140w from the 12v and 50w from the 5v lines... So, yes, any 1000w PSU should be able to cop with it, even if they spike into the 300w range during spinup.
 
nefarious986 said:
How did u come up with that estimate Arcygenical ?
Click to expand...

Most drives I've seen say their amperage requirements right on their tops... Most are around 0.5a off both lines... No telling how accurate those are... but I'd trust them, though.
 
And is staggered spin up a feature thats on the HD itself ? .. the raid controller ? .. or the motherboard .. ? .. I've not heard of this before now.

Thanks
 
Arcygenical said:
Most drives I've seen say their amperage requirements right on their tops... Most are around 0.5a off both lines... No telling how accurate those are... but I'd trust them, though.
Click to expand...

A lot of drives are speced at 1A 12v ;)
 
WD doesn't list the spin up current, but says this about the GreenPower drives:
IntelliPower - A fine-tuned balance of spin speed, transfer rate, and caching algorithms designed to deliver both significant power savings and solid performance. Additionally, GreenPower drives consume less current during start up allowing more drives to spin up simultaneously resulting in faster system readiness.
Click to expand...
One of my IDE 320GB 7200.10 drives briefly spikes to 22W during spin up measured from the wall (~15-16W from the PSU). If the WD GreenPower drives can reduce that significantly (i.e. under 1A @ 12V), that could be within the range of a normal grade PSU with appropriate rail ratings and loading. The same 7200.10 drive uses 8.5W from the wall during heavy reading and writing. I guess it's pretty "green" compared to the WD GreenPower. :p
 
During spinup, my drives used about 1.5A each on the 12v line, so my 4 rail power supply (18A per rail) couldn't handle more than a dozen at once. I tend to recommend single rail power supplies for this very reason when it comes to computers with lots of drives. As always, the Corsair 750TX that has already been mentioned will be more than enough, and you'll have a hard time finding a better deal on a decent power supply.
 
Hey BlueFox, would you happen to know what your drive use on the 5v line during spin up ?

And what equipment do you use to measure that ?
 
nefarious986 said:
Hey BlueFox, would you happen to know what your drive use on the 5v line during spin up ?

And what equipment do you use to measure that ?
Click to expand...
No idea about the 5v line. I didn't use any test equipment either. I just know that with 13 or more drives (I tried 16 initially) overloaded my 18A rail. I just a simple estimate since all the drives were identical. On the drive itself, it says they only use 0.52A on the 12v line, so it really is quite a jump during spinup.
 
nefarious986 said:
And what equipment do you use to measure that ?
Click to expand...

You need a current shunt resistor spliced into the line and measure the voltage drop across the shut (known precision resistance) which will give you the current. Google "current shunt". A quick look did not find any easily available suited for you needs. If you could find a 1 ohm 2W or .1 ohm 1/2W 1% tolerance resisteryou could get a decent idea with a DVM but the accuracy would only be fair. Actually unless you have a very good DVM its probably good enough.

Just go with the specs and add %10 for a margin. :p

Post a pic when done, would like to see that.
 
Will do, although right now, I m thinking about scaling back to 16 drives only for about 10.5TB.

You just KNOW next year they'll release a 2TB drive and the 1TB drive will drop to about $100 / piece.

Maybe a 22TB array then.

I can imagine RIGHT NOW that I'll need more than 10.5TB of data anyways. Takes a long time to fill that with just torrents. LOLs
 
You must log in or register to reply here.
Back
Top