I have a 4 year old COOLER MASTER STC-T01 CM Stacker case using dual COOLER MASTER RS-450-ACLY 450W power supplies.  I haven't done any measurements, but I am sure that the 2nd power supply is overkill for my situation.

 

Currently I have a traditional hardware Raid5 setup with1 200GB OS drive and 8 250GB WD drives in my raid array.  I am going to convert this into an unraid server starting out with three or four 2TB drives and get rid of the 250GB drives.  Theroretically, if my raid card works with unraid, I could end up with 12 drives over the years as my needs grow.

 

I am guessing that my power needs right now are as great as they will ever be since any new drives will probably be more efficient than my old 250GB drives.  Just to pick a number, let's say I currently need 300W to power my system.  With my current system, am I getting 150W from each power supply or 300W from one and the other is just sitting idle ready to be used if the first one fails?  If I don't need both of them, would I see any significant energy savings by just running one of them and not both?  There is nothing so critical that it would hurt me if I was running on one power supply and that power supply failed without the other one being able to immediately take over.

 

thanks,

Murray

Part of this depends on your CPU, mobo & memory.

Older P4's use more power then more recent core 2 duo's or the iSeries.

 

Chances are high with modern drives you can use the 450W power supply for 7-8 drives until you approach 9-12 drives.

 

The specs on that power supply are

+3.3V@30A, +5V@35A, +12V1@18A, +12V2@16A, [email protected], [email protected]

 

So to be safe you could probably support 8 drives on spin up without much issue if some of the drives are LP drives.  It surely will be able to handle more modern LP drives better then the older 250GB drives.

 

What raid card are you using, chances are it will not be supported so you will need bare SATA ports or a controller capable of providing them.  It could also be that the ports are configurable as JBOD and unRAID will see them, but for the most part this depends on the card and native kernel support.

 

After 8 drives I would consider if I could upgrade to larger drives or possibly a more efficient power supply that provided a single rail.

 

In the end there will be loss with two power supplies. Keep in mind that some power is passed off as heat and a power supply is usually most efficient within a range of operation.  So a 450w power supply supporting 4-6 drives may not be in the most efficient part of the curve.

Part of this depends on your CPU, mobo & memory.

Older P4's use more power then more recent core 2 duo's or the iSeries.

 

Chances are high with modern drives you can use the 450W power supply for 7-8 drives until you approach 9-12 drives.

 

The specs on that power supply are

+3.3V@30A, +5V@35A, +12V1@18A, +12V2@16A, [email protected], [email protected]

 

So to be safe you could probably support 8 drives on spin up without much issue if some of the drives are LP drives.  It surely will be able to handle more modern LP drives better then the older 250GB drives.

 

What raid card are you using, chances are it will not be supported so you will need bare SATA ports or a controller capable of providing them.  It could also be that the ports are configurable as JBOD and unRAID will see them, but for the most part this depends on the card and native kernel support.

 

After 8 drives I would consider if I could upgrade to larger drives or possibly a more efficient power supply that provided a single rail.

 

In the end there will be loss with two power supplies. Keep in mind that some power is passed off as heat and a power supply is usually most efficient within a range of operation.  So a 450w power supply supporting 4-6 drives may not be in the most efficient part of the curve.

I am using the Raidcore BC4852 discussed in this thread.  http://lime-technology.com/forum/index.php?topic=4952.msg48499#msg48499 with an Intel DG33FB motherboard with a 3 GHZ E6850 core2 duo processor and 4GB of ram.