Date: Thu, 14 Jul 2005 21:19:42 +0200 From: Wilko Bulte <wb@freebie.xs4all.nl> To: Kevin Oberman <oberman@es.net> Cc: freebsd-stable@freebsd.org, freebsd-questions@freebsd.org Subject: Re: dangerous situation with shutdown process Message-ID: <20050714191942.GA98637@freebie.xs4all.nl> In-Reply-To: <20050714191449.A8A615D07@ptavv.es.net> References: <42D6B117.5080302@plab.ku.dk> <20050714191449.A8A615D07@ptavv.es.net>
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On Thu, Jul 14, 2005 at 12:14:49PM -0700, Kevin Oberman wrote.. > > Date: Thu, 14 Jul 2005 20:38:15 +0200 > > From: Anatoliy Dmytriyev <tolid@plab.ku.dk> > > Sender: owner-freebsd-stable@freebsd.org > > > > Hello, everybody! > > > > I have found unusual and dangerous situation with shutdown process: > > I did a copy of 200 GB data on the 870 GB partition (softupdates is > > enabled) by cp command. > > It took a lot of time when I did umount for this partition exactly after > > cp, but procedure finished correctly. > > In case, if I did “shutdown –h(r)”, also exactly after cp, the shutdown > > procedure waited for “sync” (umounting of the file system) but sync > > process was terminated by timeout, and fsck checked and did correction > > of the file system after boot. > > > > System 5.4-stable, RAM 4GB, processor P-IV 3GHz. > > > > How can I fix it on my system? > > SCSI or ATA? If it's ATA, turn off write cache with (atacontrol(8) or > the sysctl. > > The problem is that disks lie about whether they have actually written > data. If the power goes off before the data is in cache, it's lost. > > I am not sure if write-cache can be turned off on SCSI, but SCSI drives > seem less likely to lie about when the data is actually flushed to the > drive. At least you can set FUA if you want to force the data onto the platter. -- Wilko Bulte wilko@FreeBSD.org
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