Maxtor Drives and MTBF documentation

[Axel]

guys - this just struck me as too funny and I had to post it here, as we seem to have soooo many Maxtor fans in this particular forum.

So I've mentioned MTBF before - Mean Time Between Failures or, in some places- Mean Time To Failure - it is an "industry standard" with a measurement in POH "Powered on Hours"

So I dive into a PDF file at www.maxtor.com - specifically the pdf for the Maxtor D740X-6L 20,40,60,80 ide hard drive and find several items of note -

They define MTBF as I have above, but stipulate that some people calculate it differently than others and you should know how a particular manufacturer defines their figure if you are going to use it as a "basis for comparison" - then they totally omit from the document the specifics of how they measure MTBF themselves - interesting,

BUT! - not nearly as interesting as the figure they gave for this class of drive - are you ready -

800,000 POH - you got it - 800,000 hours powered on until failure....

I find this extremely curious - lets do the math, shall we?
That works out to about 33,333.33 days - which, in turn, works out to 91.26 YEARS.....

I didn't know they were building 80GB hard drives in 1910.... must have been a government secret..... Needless to say - this is an ESTIMATE!!!

Usually - to calculate a mean, if memory serves, you have to have observations of a sample group and then you calculate an adjusted average rate of failure......

Having passed advanced graduate statistics with an A - thank you - no need to applaud - I'd say I'm qualified to state this MTBF figure must be TOTALLY BOGUS!!!

Have you ever see a 91 year old hard drive - much less a hard drive that was powered on more than 10 years straight that didn't fail???

I'd hazard a guess that these geniuses never worked with insurance actuarial tables...... I'd bet they also don't have anything to do with the department that writes the warranty documents for Maxtor.

By the way - I did a similar search on WesternDigital.com - and found nothing to compare this too - they have a simple 3 year limited warranty on the stuff I read there..... Not that I like WD HD's any better than Maxtor - they simply seem to be a bit more careful with their on-line documentation....

[Axel]

I've gone over to www.seagate.com and they have a very well laid out drive failure document that takes into account the number of up-time hours for the average user ( 2400 hours per year ) and the environment temperature and they totally lay out their calculations.

They stipulate in some documentation they expect their drives to have a 5 year service life and a 3 year warranty.

Their MTBF documentation indicates that some 7 percent of their drives fail in the first year or two, but the rest of the drives past that point can be expected to function for some 26 years after that barring unusual problems. They have a MTBF of 232,140 hours and have a high end MTBF of 389,105 hours ( 44 years )

One detail that I found to be particularly curious was that they indicated in their graphs and charts drives running at 25 degrees C failed more often than drives running at 42 degrees C - I.E. a hotter drive will last longer.......

If anyone would comment on that - I'm not sure I understand it - it seemed to me that a system would tolerate regular room temperature better than a sweltering hot summer.....

[Axel]

http://www.storage.ibm.com/hdd/library/reliab.htm

This is what IBM has to say - the cliff notes version - you don't know for sure until after it's happened....

They don't appear to post any MTBF figures - but do stipulate in the above white paper they know that term and others and use them internally......

Another interesting term they have is DPPM - defective parts per million...... it's just a term - the figure might be 500,000 DPPM which isn't that impressive - again - they don't release that info to us "public" types....

This is fun - lets see what other info I can find....

[Mntsnow]

I'm betting that you came accross a typo. When you are figuring 91 years I bet they had it figured for 9.1 note the POINT :D 9+ years for an IDE drive is a long time...

[Axel]

I went looking at Samsung and Fujitsu as well -

I think the person writing the spec's, and I suspect it was the same person, accidentally leaned on the 5 and 0 keys at the same time for varying periods of time - see if this seems fishy to you as well -

Both manufacurers list a 500,000 POH MTBF figure, 50,000 start/stop cycles and a 5 year expected life time - in that order on both spec sheets...... nice neat - round figures....

57 years MTBF -

So - as Maxtor swallowed up Quantum's hard drive division, that covers every recognized major hard drive manufacturer out there....

The gap between the warranty ( typically 3 years ) the service life ( typically 5 years ) and the mean time between failures ( from 26 years to 91 years if documented ) is too great for me to even seem truthful. I'm seeing Seagate in a better light this time and may opt to buy a drive from them my next time out. That is unless the Quantum hard drive division rebels and pulls away from Maxtor..... hehehe

[jadison]

Those are some interesting figures...I've had personal experience with Western Digital drives and they've lasted for as much as 10-12 years. One drive is still running made back in 1987.

As for Maxtor, I only have a Diamond Max 15GB that's going on its 3rd year.

I personally use WD because of the experience I've had with their drives, and the fact that they work well and don't fail when a system is OC'ed (properly, and not to the Xtreme, hehe)

Thanks for doing all the research, it helps to know that someones doing it...I'll take a look @ some of those sites later on too.