💾 Archived View for gmi.noulin.net › mobileNews › 242.gmi captured on 2024-08-19 at 07:13:59. Gemini links have been rewritten to link to archived content
⬅️ Previous capture (2024-05-10)
-=-=-=-=-=-=-
2007-08-09 17:39:39
Is this reason why we cant spin down disks?
(Score:4, Interesting)
by grims (602269) on Wednesday August 08, @06:33PM (#20163309)
On of my gripes with Linux is that one cannot spin down the disks to lessen their wear and tear.
Ive been told that the kernel constantly needs to access the disk...
Is this the reason of something else prevents the disks from spinning down?
Re:Is this reason why we cant spin down disks?
(Score:5, Informative)
by rahvin112 (446269) on Wednesday August 08, @07:34PM (#20163875)
Stopping and Starting a disk causes the most wear on the disk. When in an idle state the spinning disk has fully lubricated bearings and is using just a tiny amount of energy. Strap in a stop and start and you have bearings on start that don't have their lubrication optimally spread (gravity and lack of motion cause the metal to get closer together and depending on the manufacturer may have some of the bearings without lubrication), and the spinup of the disks themselves is on average a 6W draw (idle is like .3W). Plus, when the disks are fully spinning wobble is going to be constrained a bit by the speed, whereas on startup and stopping the minor imperfections in the disk can let the minor wobbles show which strains the bearings and causes wear and tear. See if the bearings start to fail and are say 20% shot, the motor on the drive can just use a little more energy to drive them, but the startup cost might exceed what the motor is capable of outputing. Using the example above, the .3W draw on idle might
climb to .6W, but on startup that could translate in moving from 6W to 12W (and exceeding what the motor can physically provide).
And if you don't believe any of that you shouldn't have any trouble using google to find Admins who tell horror stories about having to reboot a drive and losing the entire drive because the bearings were shot to the point that once the disks stopped the motor couldn't generate enough force to restart them. But the disk could have lasted years more as long as it wasn't stopped. In fact in companies where a lot of data is stored the disks are put on their own power source at least partially because the disks don't have to be stopped if a server needs to be rebooted because of failure or updates. This is also one of the reasons to be wary of purchasing used storage arrays. Might have worked great when they shut it off, but you might be able to restart the array.