[SATLUG] Re: [XCSSA] Recommendations for a SAMBA/NAS device?

Tweeks tweeks at rackspace.com
Thu May 21 13:54:31 CDT 2009


On Thursday 21 May 2009, X-otic Computer Systems of San Antonio wrote:
> Actually Tweeks, I disagree with you :)
>
> Drives consume what like 15W per drive (I'll have to look it up but I
> don't have much time as I'm in a break from training). You do not need
> a RAID card to spin the drives down, either. 'hdparm' should be able
> to take care of that, even on SATA drives.

Maybe if you're running SW-RAID.. (blech!)... but no workie on most hardware 
RAID systems man.  You typically can't send direct drive level commands to 
the individual drives (unless you have one of the few magic RAID cards out 
there that allows this AND/or the kernel module that allows for this).


> As for the CPU, modern procs chew up 100W of power. Even the low power
> modern chips hum away at 65W. So, it indeed makes sense to use a lower
> power CPU that draws 5-10W assuming that CPU is powerful enough for
> your application (which a NAS qualifies). Those chips also throw off
> far less heat (some can be totally cooled passively) which,
> indirectly, impacts your cooling bills.

Well.. even non-server grade (12-15W) drives in a large array (9 drives) is 
135Watts.  But "real drives" (e.g. 15k cheetah drives or Hitachi SATA) idle 
at  15W.. But when in full seek, this can pop up 20 22watts (x9 ~200watts!).

So yeah.. going to a low power proc is a good idea.. but spinning down drives 
not in use gets you more power savings.



> Similarly, software RAID is probably all you need. 

Blech!  Tim.. You are dead to me!  ;)


Tweeks


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