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Re: ATA Drive Selection (Reliability)...

> * Another point on reliability that was published on this list very
> recently is MTBF linked to the heat. It was noted 50% reduction
> in MTBF with a 3 degree celcius increase.

Yes... I must agree.

We have quite a number of IBM Deskstar 120GXP drives with 3ware cards
running RAID5. Some of you may remember me bitching about 3ware card's
inability to handle problems and errors elegantly (no way to replace a
failed drive easily if you have a hot spare, as the hotspare takes over
the failed drive's job, and you can't get the hotspare back to being a
hotspare anymore... anyway, thats a different story).

Basically, long story short... we had a bunch of DOA "click of death" IBM
drives... yes.. NOT 75GXP drives... but 120GXP drives that weren't suppose
to have this problem. Anyway, once we got rid of those DOAs, out of the
remaining working ones, the IBMs run the HOTTEST of all drives out
there... compared to WD, Seagate, Maxtor (and probably most others). This
was done using the informal "touch with finger" test and not with
thermometers or anything though, so don't quote me.

Anyway, a few servers had 2 small cooling fans per hard disk (blowing air
in from the from the front of the case), while a few servers had 1 big fan
drawing air in from inside the case. Air flow wise, the small fans moved
more air overall (4 hard disks, 2 fans per hard disk, 8 fans total). Those
servers have had less drive problems...less errors during high loads, etc.
The ones with the one big fan drawing air have numerous problems.

So I am one of the believers that the "click of death" (other than the
ones DOA) is caused by heat problems, and not the "pixie dust", motor arm
failure, magnetic touch-point moving, etc.. Others say it is for other
reasons... YMMV.

IBM hard disks... with the superior cache algorithms, provide the highest
RAID 5 performance under high load of any drives available now... even
those ones with big 8Mb cache (was that WD or Seagate? anyway...). In
single drive mode, they are just average.

So if you want high performance under RAID 5, go with IBM, and remember to
provide good cooling.

Not sure about the most recent drives though... this comparison was done
about 6-8 months ago.

Hope this additional info helps.

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