On Monday 13 November 2017 11:40:17 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). > >>> > >>> I've investigated that, and I have amanda wrapped up in a script > >>> that could do that, but ran into a showstopper I've long since > >>> forgotten about. Al this was back in the time I was writing that > >>> wrapper, years ago now. One of the show stoppers AIR was the fact > >>> that only root can mount and unmount a drive, and my script runs > >>> as amanda. > >> > >> While such a wrapper might work if you use sudo inside it (you can > >> configure sudo to allow root to run things as the amanda user > >> without needing a password, then run the wrapper as root), what I > >> was trying to refer to in a system-agnostic manner (since the exact > >> mechanism is different between different UNIX derivatives) was > >> on-demand auto-mounting, as provided by autofs on Linux or the > >> auto-mount daemon (amd) on BSD. When doing on-demand > >> auto-mounting, you don't need a wrapper at all, as the access > >> attempt will trigger the mount, and then the mount will time out > >> after some period of inactivity and be unmounted again. It's > >> mostly used for network resources (possibly with special > >> auto-lookup mechanisms), as certain protocols (NFS in particular) > >> tend to have issues if the server goes down while a share is > >> mounted remotely, even if nothing is happening on that share, but > >> it works just as well for auto-mounting of local fixed or removable > >> volumes that aren't needed all the time (I use it for a handful of > >> things on my personal systems to minimize idle resource usage). > > > > Sounds good perhaps. I am currently up to my eyeballs in an > > unrelated problem, and I won't get to this again until that project > > is completed and I have brought the 2TB drive in and configured it > > for amanda's usage. That will tend to enforce my one thing at a time > > but do it right bent. :) What I have is working for a loose > > definition of working... > > Yeah, I know what that's like. Prior to switching to amanda where I > worked, we had a home-grown backup system that had all kinds of odd > edge cases I had to make sure never happened. I'm extremely glad we > decided to stop using that, since it means I can now focus on more > interesting problems (in theory at least, we're having an issue with > our Amanda config right now too, but thankfully it's not a huge one). > > > 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). > > > Interesting, I had started a long time test yesterday, and the > > reported hours has wrapped in the report, apparently at 65636 hours. > > Somebody apparently didn't expect a drive to last that long? ;-) > > The drive? Healthy as can be. > > That's about 7.48 years, so I can actually somewhat understand not > going past 16-bits for that since most people don't use a given disk > for more than about 5 years worth of power-on time before replacing > it. However, what matters is really not how long the device has been > powered on, but how much abuse the drive has taken. Running 24/7 for > 5 years with no movement of the system (including nothing like > earthquakes), in a temperature, humidity, and pressure controlled room > will get you near zero wear on anything in the drive but the bearings > and possibly the heads. In contrast, that same five years of runtime > in a laptop that's being taken all over the place will usually result > in a drive that has numerous errors in addition to noticeable > mechanical wear.
Which makes perfect sense. Although, I have a lappy that has at least 5000 miles worth of hammering from a twin piston pounder hauling me around putting out technical fires at tv stations in its history, and that 100gig drive is still doing ok last time it was powered. But not recently, couple times in the last year I often use it as a test bed to check out a new distro, has mint 14 on it ATM. Getting old. 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>
