On Tue, 26 Jan 2010 20:17:23 +0100 (CET) Alexander Best <alexbes...@wwu.de> wrote:
> hi there, > > because of kern/140752 i looked through a discussion back in 2009 > (http://lists.freebsd.org/pipermail/freebsd-hackers/2009-March/027879.html) > concerning freebsd's hdd spin down procedure. right now ATA_FLUSHCACHE is > being used although the hitachi hdd specs referenced in the pr say that this > will not cause proper load/unload and thus an emergency unload will occur > which reduces the life expectancy of hdds dramatically (20.000 shutdowns vs. > 600.000 shutdowns). unfortunately the discussion back then didn't come up with > any sort of decision/patch. > > attached you'll find a very simple patch which issues ATA_STANDBY_IMMEDIATE > instead of ATA_FLUSHCACHE during hdd spin down. > > could somebody with hdd knowledge comment on this? this matter seems quite > important since there may be a chance that the current spin down mechanism in > freebsd damages hdds! > What if the disk doesn't support ATA_STANDBY_IMMEDIATE? Your patch then negates the benefit of calling ad_shutdown(), namely flushing the cache, if possible. I suggest putting your new code at the top and leaving the old code in an else-if clause. --- Gary Jennejohn _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
