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ReadyNAS RN42400 OS 6.8 to ReadyNAS RN42400 6.8 Mirror
I purchased a second ReadyNAS 42400 w/ "indentical" 2T drives and want to "mirror" the second NAS to the primary. I see Netgear has at least two ways to back up a NAS but it's not clear which is the...
It was a while ago that I posted that, I don't recall who the respondent was at this point (or if he is still active).
I don't believe he was saying that the air bearing wouldn't fail, I think he was just saying that he didn't believe frequent spinups would cause them to fail faster than drives that were spinning 24/7.
Causes I've seen reported include electrical component failure, physical contamination, mechanical arm failures, and motor failures.
I know for certain that enabling spin down (and putting NAS on power schedules) saves power, and I don't have any clear data that says whether it increases failure risk or decreases it. In the absense of that data, I enable spin down and use power schedules.
Stephen,
Like I said, trade secrets - don't expect public data. It was 1995 when I left IBM. I was in a group whose job it was to determine how disk drives died. 1995 was how many generations of disk drives ago? I have no clue where the real failure culprit is now. I do KNOW, heat and mechanical failure is always the culprit. I just don't know exactly where in modern drives. I'll bet money the drive manufacturers don't know either. Or they'd fix it like IBM did at that time. A five-year MTBF is a poor-quality product by today's standards. Back when, the air bearing wasn't the big problem other than it didn't like gunk on it. There must have been big improvements or we couldn't get cheap terabyte drives today.
As for the mechanical engineer's opinion - if you get a chance, ask him what the failure mechanisms are nowadays. Heads seem to still crash. My DVR's drive is starting to fail. I guess that new air bearing is having troubles or are parts of the disk surface just flaking off.
I've been looking for an IBM Technical Disclosure Bulletin I authored years ago where we devised circuitry to zero out the contact potential between a head and disk. With no surface tension no particles stuck to the heads. Our test system, heavily accelerated, lasted for an equivalent 20 years or more. I also established a large matrix of drives with regulated particle injection. Guess what, the drives with the greatest amount of stainless steel particles crashed before the cleaner drives. Got me a big bonus for inventing a servo controlled particle generator and my collaborator a BIG promotion. But not made public. All moving parts shed particles. If they can stick to the head's air bearing surface it will screw up the air bearing and ultimately cause a crash. But that's an opinion...
Thanks again!!!
It was a while ago that I posted that, I don't recall who the respondent was at this point (or if he is still active).
I don't believe he was saying that the air bearing wouldn't fail, I think he was just saying that he didn't believe frequent spinups would cause them to fail faster than drives that were spinning 24/7.
Causes I've seen reported include electrical component failure, physical contamination, mechanical arm failures, and motor failures.
I know for certain that enabling spin down (and putting NAS on power schedules) saves power, and I don't have any clear data that says whether it increases failure risk or decreases it. In the absense of that data, I enable spin down and use power schedules.
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