> * 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.
