i also have such a drive (damn, if i knew that saving some Watts would hurt...) - and i measured ~100 load_cycle_count per hour, which is _way_ to much, imho. if we trust the spec, the disk would be dead after ~1year. it seems that "intellipark" is not that intelligent as it should be and a little bit too agressive. from what i have found, the time for parking the heads is much below the linux kernel flush interval (which seems to be at 30secs), so i think the best thing to do is tuning either dirty_expire_centisecs and dirty_writeback_centisecs (defaults to 3000/500 on my system) or tune the disk parking interval , so that the disks own interval is greater than the linux flush interval. i also openend an SR at WD - will see if they will recommend that dos utility, too. >I got back from WD's tech support and received a DOS utility which can control >this drive feature, apparently using vendor specific commands. With it head >unload timer can be disabled or set to a period between 100ms and 25.5s. doh - so that disk always is faster with parking it`s heads than linux default flush interval !? btw - is that dos utility available for download somewhere? regards roland List: linux-kernel Subject: Re: Western Digital GreenPower drives and Linux From: "Tvrtko A. Ursulin" <tvrtko () ursulin ! net> Date: 2008-04-10 7:48:08 Message-ID: 200804100848.08442.tvrtko () ursulin ! net [Download message RAW] On Wednesday 09 April 2008 21:18:35 Tvrtko A. Ursulin wrote: > I got one of them (WD5000AACS) recently and to my horror after less than > three days of being power on this is what I saw: > > 9 Power_On_Hours 0x0032 100 100 000 Old_age Always - 66 > 193 Load_Cycle_Count 0x0032 197 197 000 Old_age Always - 10233 > > At this rate the disk would reach it's design limit for load/unload cycles > in around 80 days. Not good - so I implemented a lame workaround of keeping > disk busy every couple of seconds - hopefully that won't kill it sooner > that unloads would.. > > I am also currently talking with first line of WD's tech support trying to > get some data on how exactly those drives manage head unloading, but that > may not lead anywhere useful. I got back from WD's tech support and received a DOS utility which can control this drive feature, apparently using vendor specific commands. With it head unload timer can be disabled or set to a period between 100ms and 25.5s. Of course I asked for more than a DOS utility, but the question really is how was this feature intended to work with Windows for example, is there something there which would prevent such rapid load/unload cycle growth, and why isn't it documented somewhere? I am kind off hoping that someone from WD is reading this list and will notice this in case my effort with tech support fails. Tvrtko _________________________________________________________________________ In 5 Schritten zur eigenen Homepage. Jetzt Domain sichern und gestalten! Nur 3,99 EUR/Monat! http://www.maildomain.web.de/?mc=021114 -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
