[LINK] Leave on, or turn off?

[Kim Holburn]

On 2006/Nov/30, at 1:54 PM, grove at zeta.org.au wrote:
> I tend to leave my gear on 24x7 unless there's a storm approaching
> or if it's a heatwave prediction - we don't have air conditioning  
> at home!
>
> Most hard drives have MTBF ratings (Mean time between failure) of  
> values exceeding 80,000 hours or more.   These ratings are  
> determined by running the disks at sea level and room temperature  
> (about between 20-30c) constantly at full power.   If you run your  
> disks at higher temperatures, you start to get a 4x drop in life  
> expectancy
> as you get closer to 40c.
>
> With electronics, it's the capacitators and high energy components  
> likely to go first.   Generally the power supply is the thing that  
> is likely to become unstable as the capacitators start to age or  
> dry out.   Fans are the worst - cheap nasty fans with no grease in  
> the bearings are the things that lead to more failures than  
> anything else.   Lose the fan and it silently raises the internal  
> system temperature until things start to go wrong!

I don't see why capacitors should be a problem but there was in the  
last few years a whole batch (from a particular factory? In China?)  
that were bad and all had to be replaced, millions of them.  Would  
this have skewed the figures?

About 5 years ago I and a colleague installed a group of servers with  
no moving parts at all.  Mini-ITX systems with OS on flash memory, no  
fans.  They are still working perfectly.  We have had one power  
supply failure in that time and a couple of them are getting a little  
underpowered as needs grow but that's it.  We had one problem getting  
them working initially as most linux systems use human input and hard  
disk latency to provide entropy and these had neither.

Getting rid of fans is the key, it's also the key to having any home  
servers that are bearable to share a house with but it's getting  
harder with modern CPUs.


--
Kim Holburn
IT Network & Security Consultant
Ph/F: +61 2 62577881 M: +61 417820641
mailto:kim at holburn.net  aim://kimholburn
skype://kholburn - PGP Public Key on request

Democracy imposed from without is the severest form of tyranny.
                           -- Lloyd Biggle, Jr. Analog, Apr 1961