Date: Fri, 19 Jul 1996 16:25:39 +0200 (MET_DST) From: y0002257@ws.rz.tu-bs.de (Sven Brandenburg) To: freebsd-scsi@FreeBSD.org Subject: Re: turning off scsi disks Message-ID: <9607191425.AA78962@rzrtr1.rz.tu-bs.de>
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Above all thanks for your answers, Wilko Bulte writes: > You better be a bit careful with this. The very nice MTBF figures we > see these days are definitely not spec'ed by a system turning the > drive on/off every couple of minutes. At least not if the drive > was not designed for this. Well, apart from the fact that repeated spindown of your disks doesnīt really *increase* the MTBF I would like to have the possibility of doing so! My problem is not having the harddisks run while working - They do not have to spin down every minute - I want to turn them off when there`s no load what so ever. Therefore the time before a disk receives its STOP unit should be well over five (maybe ten) minutes without disk activity - so these occasions are presumably very rare when working. (Which then shouldnīt decrease MTBF that much.) I would be entirely happy to let the disks do this on their own - without the need to hack the sources. There are older disks who implemented such a feature but unfortunately I donīt know whether my disks have such nice thing nor how to activate it - all I know is that it works for an old 40Meg Quantum disk - There was a short front end running on the Amiga which allowed to set the spin off time and to make a decision whether to put this information permanently onto the disk or just until reboot. When saved permanently the harddisk would turn off after that given time - even after switching the scsi host and system. I want to have exactly this! J. Wunsch wrote: > Making it spin down while being idle would require additional timers > in the driver, but should not be undoable. However, the hook to turn > it on must be moved into the sdstart routine then (perhaps activated > by some additonal flag in the sd_data structure that is being set by > the timeout handler when spinning it down). When do we start working on it ;-) As you may have noticed I am new to FreeBSD (not to computers, though) and canīt imagine how much work this could be (shame on me - Iīve never taken a look on the related sources.. I will do right now..) BUT: Am am willing to learn! :-) Thank you very much for your time. ---- I will not trust you, I, Nor longer stay in your company. Your hands than mine are quicker for a fray: My legs are longer though, to run away. William Shakespeare, A Midsummer Night`s Dream, 1596
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