Re: RAID Class Drives`

[Eric Shubert <ejs@shubes.net>]

Bill Davidsen wrote:
> Joachim Otahal wrote:
>> John Robinson schrieb:
>>> On 18/03/2010 16:45, Joachim Otahal wrote:
>>>> [...]  You should take care of the temperature of the drives,
>>>> 30°C to 35°C is preferred, above 35°C the lifespan goes down, over 
>>>> 40°C rapidly down.
>>>
>>> Do you have a reference for this? Most drives' operating temperature 
>>> range is specified up to 55°C, sometimes higher for enterprise 
>>> drives, without any indication (apart from common sense perhaps) that 
>>> running them this hot reduces lifespan.
>>>
>>> Cheers,
>>>
>>> John.
>>>
>> About a half year ago the german publisher c't did this testing (or 
>> reported from a big testing, cannot remember) what the best 
>> temperature of desktop drives is. The statistic varied from drive to 
>> drive since some are less than 5°C over room temperature, others are 
>> 15°C or more over room temperature (of course mounted behind a silent 
>> fan which keeps the air moving, no turbine mode).
>> The result was that 10°C and 15°C are not good for the drives. The 
>> "perfect sweet spot" changes from drive to drive (even within on 
>> manufacturer), but all of them had their sweet spot somewhere around 
>> 20°C to to 35°C with variation in the range of measurement error.
>> Some drives has a higher failure rate at 40°C, for some 55°C was no 
>> problem at all and showed no real change in the failure rate. The last 
>> two examples were the extreme cases.
>>
>> Some of my drives are 2°C above room temperature, others are 12°C over 
>> room temperature. Sine I really take care that non reaches 40°C even 
>> in summer the failure rate got down from "every few month" to once in 
>> the 3 years which is the time I really take care of the drive 
>> temperatures. There are 6 drives currently in use from 750GB (the 
>> hottest of all my drives) up to 1.5 TB in my private machines, only 
>> one of them shows a gradual change in the SMART values (reallocated 
>> sector count), which mean it will probably fail in about 1.5 years if 
>> the error rate stays constant. At work (at least the two machines 100% 
>> under my control) I had the same effect, keep the HD's cool and they 
>> will live long, let them get over 40°C and be ready to replace them soon.
> 
> 40°C is a good target, readily available to people in the Arctic. It 
> requires a lot of cooling to do it in normal climates where the ambient 
> may be mid to high 40s. Fortunately my experience looks more like 
> Google's, as long as you move enough air over the drive to avoid hot 
> spots they seem to do well, hitting 43-46 much of the time. If I replace 
> them because they're obsolete and working, they lasted long enough. 
> Perhaps being "always on" is part of longevity, the ones I have on for 
> 5-6 years seldom fail, the desktop cycled daily maybe half that.
> 
> I do note that the WD drives run about 8°C cooler than Seagate. That's 
> the "black" drive, I guess, the "green" drives would run cooler, based 
> on power use. I will switch to them next build.
> 

I find this whole discussion of drives interesting. Thanks to everyone 
for their input.

A thought occurred to me today. Realizing that the drives are generating 
heat, *if* it's true that drives which run hotter have a shorter 
lifetime (which is debatable), it's possible that the cause of heat 
generation (friction?) is the contributing factor to the shorter 
lifetime, and not the heat itself. IOW, if a drive runs hot, removing 
the heat more quickly (reducing its operating temp) wouldn't necessarily 
increase the drive's lifetime.

Just a thought.

-- 
-Eric 'shubes'

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