This message is from the T13 list server.
On Tuesday 27 April 2004 00:15, Pat LaVarre wrote: > This message is from the T13 list server. > > > I asked about this originally, > > Hi, thanks for sharing your personal history of pain. > > > > The natural implicit result is then a maximally accelerated test til > > > failure: read, park, repeat, indefinitely. > > > > ... that is exactly what these drives do, with "advanced power > > management" enabled (which it is by default) ... > > > > the implications ... are making me (and many other people) blue. > > I haven't yet heard these devices are operating out of spec. > > Yes, if operating within spec actually promises short life in a system, > then naturally I see first the customers of that system, then the vendor > of that system, then the supplier of the devices, will feel pain. That is precisely the problem. Some drives auto-park by default every 10 seconds. Most UN*X type systems (I think including MacOS X) sync things to the disk every 30 or 60 seconds. This means that the drive parks and then very soon unparks, repeatedly. We've seen many cases where the "load cycle count" number multiplied by 30 is almost identical to the total operation hours of the drive. The party line from drive vendors seems to be that "the drive is only rated for 300000 load/unloads". Well, gee, thanks, I do know how to read. Do the arithmetic. That means the drive is, in the worst case, rated for 10*300000 seconds, or 34.7 days. 99.9% of people would not consider a disk lifetime of 34.7 days even vaguely reasonable. To be blunt, it's asinine. And, yet, THIS IS WHAT THE DRIVES DO OUT OF THE BOX. To make matters worse, while one brand of drives can be made to not do this by turning off "advanced power management," with another brand turning off this misfeature means that the drive can leave the head over the same spot on the disk indefinitely -- and I don't think I need to remind people here what happened to some IBM drives a few years ago when they exhibited *that* behavior. The only sure-fire solution I've found is to make the software read a random sector periodically, to keep the drive form auto-parking, and to keep the head moving a bit. It is my considered opinion that I should not have to do this to make the hardware reliable. I guess what I was looking for here is: 1) Do people think this behavior in a disk drive is sane? 2) Are there known reliability issues with existing or past drives that have had this behavior? 3) Is there some other workaround that I've missed? 4) Maybe some drive vendors could comment on what they do, and why.
