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    SubjectRe: Western Digital GreenPower drives and Linux
    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
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