Date: Wed, 20 Sep 2000 11:20:46 +0200 (CEST) From: Soren Schmidt <sos@freebsd.dk> To: tlambert@primenet.com (Terry Lambert) Cc: archie@whistle.com (Archie Cobbs), fs@FreeBSD.ORG, sos@FreeBSD.ORG Subject: Re: disable write caching with softupdates? Message-ID: <200009200920.LAA66651@freebsd.dk> In-Reply-To: <200009200818.BAA27874@usr01.primenet.com> from Terry Lambert at "Sep 20, 2000 08:18:51 am"
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It seems Terry Lambert wrote: > > > > Isn't it safer (in the face of a power failure) to disable write > > > > caching on a hard disk when softupdates is in use? > > > > > > Yes. You _must_ guarantee that the drive does not complete > > > writes out of sequence that it reports having completed in > > > sequence. Hardware which lies is evil. > > > > Hmm, the write caching on ATA drives (if they support it at all, > > very few actually does), is guarantied to be able to write the > > data to disk on power failure, or at least so they say, and I've > > not been able to prove otherwise. > > The ATA drives Whistle is using, which is what I'm assuming > Archie is on about, do _not_ support this facility. As far > as I can tell, there wre some SCSI drives manufactured by > IBM at one time which could do this, and some lab drives at > Quantum (also SCSI). Hmm, well, lets disable this then, there is no need to complicate things :) -Søren To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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