[mythtv-users] new rig ... help with specs

[Brian Wood]

On Wednesday 23 September 2009 07:24:29 jedi wrote:
> On Tue, Sep 22, 2009 at 09:34:04AM -0600, Brian Wood wrote:
> > On Tuesday 22 September 2009 09:23:27 Chris Stevens wrote:
> > > The situation with RAID hard drives is fairly straight-forward: buy the
> > > enterprise versions - eg. Seagate 750 ES. These have MTB of around
> > > 3,000,000 hours which is over 300 years and are only a bit more
> > > expensive.
> > >
> > > But there is just one primary rule for any HD: KEEP THEM COOL. Drives
> > > go very quickly if you let them overheat. You can actually buy any old
> > > rubbish so long as you follow this rule.
> >
> > I would think so as well, but:
> >
> > The Google paper on hard drive reliability seemed to contradict this
> > seemingly common sense idea.
> >
> > They were unable to show much of a correlation between temperature and
> > failure rates.
> >
> > I (and many others) found this odd.
> >
> > I still try and keep my drives as cool as possible, electronics in
> > general likes cooler temperatures, but I think about it more now, having
> > read the Google paper.
>
>     I once had a Sun NUMA machine that my company quite literally kept
> in a closet. This company was in the desert so we had the usual 115
> degree summer temperatures. The AC in that building was shoddy and the
> temperature in our "server" room was often over 100.
>
>     When the matter was discussed with Sun support they told us that the
> temperature wasn't important as much as temperature fluctuations were.
> They said that if the room is going to get to 100 then it should stay
> there all the time and not go back and forth between 70 and 100. The
> fluctuations are what will cause the hardware to fail.
>
>     It was a really weird situation all around...


Not so weird. Changes in temperature are what cause chips to wiggle themselves 
out of sockets, and the differential expansion and contraction caused by 
temperature changes can cause solder joints to fail, boards to crack and the 
like.

I think Sun's advice was sound.

-- 
Brian Wood
beww at beww.org