Haven't read back through the whole thread, but I'm going to comment anyway.
SMART isn't very smart. If you plan on relying on this metric alone to keep your data safe, then you are going to be losing data all too frequently. It's a well known fact in the industry that SMART doesn't really work a *large* percentage of the time. If anyone wants to challenge me on that, I'll google it and dig up some statistics and white papers and hard evidence. Unfortunately, the best hard evidence is hidden behind the closed doors of the makers. I've had drives last for decades and others 1 day. Fast/low, cheap/expensive all the same. Also don't think that going out and buying an expensive SCSI will shield you from this. It's been proven that SCSI/IDE/SATA are all pretty much equivalent, and that buying an expensive one isn't going to boost your longevity either. Want reliable harddrives, then your best bet is to buy a disk array from one of the top packagers. But really the best bet is to buy a pair or three, do frequent backups, don't run 24/7, occasionally mirror to a spare.
As far as stress testing HDs, I think that's foolhardy. It's a good way to destroy HDs. I used to do this for a living for a company that made blood analsying equipment. Burn the drives in and stress them over a period of weeks, discard the ones that failed, and installed the ones that didn't. This weeded out the ones from bad lots, but I can't help but wonder if we didn't reduce the life of those "good" drives by doing this. Drives were different back then too, not as dense and a whole lot more expensive (oh yeah and less storage). --- Oren Beck orenbeck@gmail.com wrote:
In regard to the concept of drive degradation being "hidden" by controllers. It seems to be a needful evil for the current applied art and science of rotating magnetic media at these price points. Yes, I suspect we "could" make media, heads, positioning methods et all that would be "true" non contact under most practical conditions.
The game is a paraphrasing of an older tech rubric- Cheap- Fast- Stable=pick any 2.
So the SMART ancestral concept was actually devised as an end run around those rules.
P.S. SMART was really just a marketing tool.
On Tuesday 10 July 2007 10:19:44 pm Jack wrote:
the best bet is to buy a pair or three, do frequent backups, don't run 24/7, occasionally mirror to a spare.
While I agree that there's little point in stress testing a drive that's going to be used, I find some of your other assertions would be a lot more credible if you cited some references for them. I have had SMART monitoring catch a drive that was starting to go bad, and I am reasonably certain that there are certain classes of hard drive that do receive better quality control than the commodity drives we get at BestBuy or through the local OEM suppliers.
That said, you can't simply rely on price or the fact that a drive is SCSI or sold as a "server drive", you need to know what is actually done by the manufacturer to provide improved reliability.
As far as running 24/7 though, I really have to disagree there. For 99% of electronic devices, the greatest stress they undergo is at start-up, where cool, idle parts are spun up to speed and temperature, and surges of electrical and magnetic force apply physical stresses to the components.
In about 20 years of maintaining PC's, I've seen more component failure, including hard drives, in systems that were switched on and off every day than in ones that ran 24/7.
Good, tested restorable backups are the only way to be sure.
Cited references:
http://209.85.163.132/papers/disk_failures.pdf http://www.grc.com/sn/notes-081.htm
I could give you more, if you'd like. Or you could simply google yourself for things like "SMART disk failure".
I wasn't advocating that *ALL* repacking vendors were created equal. Anyone who would spend the money to buy such a setup would be a fool not to do the proper research first. Yes, I know the world is full of fools. My comments weren't aimed at them. I also don't like to advertise for companies on mailing lists, so you won't often see me freely offer a vendor without being asked first.
Brian,
*My opinions are my own and my interpretations may differ from yours. That's what makes us unique, so YMMV* ;')
--- Jonathan Hutchins hutchins@tarcanfel.org wrote:
On Tuesday 10 July 2007 10:19:44 pm Jack wrote:
the best bet is to buy a pair or three, do
frequent
backups, don't run 24/7, occasionally mirror to a spare.
While I agree that there's little point in stress testing a drive that's going to be used, I find some of your other assertions would be a lot more credible if you cited some references for them.
-
Jack -
Jonathan Hutchins