On Monday 13 November 2017 13:42:13 Jon LaBadie wrote: > On Mon, Nov 13, 2017 at 11:40:17AM -0500, Austin S. Hemmelgarn wrote: > > On 2017-11-13 11:11, Gene Heskett wrote: > > > On Monday 13 November 2017 10:12:47 Austin S. Hemmelgarn wrote: > > > > On 2017-11-13 09:56, Gene Heskett wrote: > > > > > On Monday 13 November 2017 07:19:45 Austin S. Hemmelgarn wrote: > > > > > > On 2017-11-11 01:49, Jon LaBadie wrote: > > > > > > > Just a thought. My amanda server has seven hard drives > > > > > > > dedicated to saving amanda data. Only 2 are typically > > > > > > > used (holding and one vtape drive) during an amdump run. > > > > > > > Even then, the usage is only for about 3 hours. > > > > > > > > > > > > > > So there is a lot of electricity and disk drive wear for > > > > > > > inactive drives. > > > > > > > > > > > > > > Can todays drives be unmounted and powered down then > > > > > > > when needed, powered up and mounted again? > > > > > > > > > > > > > > I'm not talking about system hibernation, the system > > > > > > > and its other drives still need to be active. > > > > > > > > > > > > > > Back when 300GB was a big drive I had 2 of them in > > > > > > > external USB housings. They shut themselves down > > > > > > > on inactivity. When later accessed, there would > > > > > > > be about 5-10 seconds delay while the drive spun > > > > > > > up and things proceeded normally. > > > > > > > > > > > > > > That would be a fine arrangement now if it could > > > > > > > be mimiced. > > > > > > > > > > > > Aside from what Stefan mentioned (using hdparam to set the > > > > > > standby timeout, check the man page for hdparam as the > > > > > > numbers are not exactly sensible), you may consider looking > > > > > > into auto-mounting each of the drives, as that can help > > > > > > eliminate things that would keep the drives on-line (or make > > > > > > it more obvious that something is still using them). > > ... > > > > But if I allow the 2TB to be unmounted and self-powered down, > > > once daily, what shortening of its life would I be subjected to? > > > In other words, how many start-stop cycles can it survive? > > > > It's hard to be certain. For what it's worth though, you might want > > to test this to be certain that it's actually going to save you > > energy. It takes a lot of power to get the platters up to speed, > > but it doesn't take much to keep them running at that speed. It > > might be more advantageous to just configure the device to idle > > (that is, park the heads) after some time out and leave the platters > > spinning instead of spinning down completely (and it should result > > in less wear on the spindle motor). > > In my situation, each of the six data drives is only > needed for a 2 week period out of each 12 weeks. Once > shutdown, it could be down for 10 weeks. > > Jon
Which is more than enough time for stiction to appear if the heads are not parked off disk. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene>
