Date: Mon, 12 Mar 2001 15:53:10 -0800 (PST) From: Matthew Jacob <mjacob@feral.com> To: Alfred Perlstein <bright@wintelcom.net> Cc: "Justin T. Gibbs" <gibbs@scsiguy.com>, Soren Schmidt <sos@freebsd.dk>, Kevin Oberman <oberman@es.net>, scsi@FreeBSD.ORG, fs@FreeBSD.ORG, dillon@FreeBSD.ORG Subject: Re: Disk I/O problem in 4.3-BETA Message-ID: <Pine.LNX.4.21.0103121546290.31161-100000@zeppo.feral.com> In-Reply-To: <20010312154452.K18351@fw.wintelcom.net>
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> > If you need everything sync'd, you'll have to explicitly have the da driver > > send the SYNCHRONIZE CACHE command. > > Afaik we never depend on actually B_ORDERED'd data, at least not > for filesystem consistancy (as afaik it would violate USL patents). Hmm? Wasn't there an assertion about this from Terry IIRC? Huh.. as far as I remember Steve Kleiman was talking about this at Sun in 1990- dunno if this has any pertinence to the patent or usage. > We really don't need the SYNCHRONIZE CACHE either, basically a B_FLUSH > would be nice, the problem I see is making sure it doesn't get eaten > by the millions :) of OR's and AND's on the b_flags fields. Well, if I understood your mail, you were trying to find out a way to live safely with not only ordering (which is done in s/w with softupdates for FreeBSD, right?- last I heard from Steve Tweedie was that he was considering using tags for ordering in ext3) but also to try and live safely with data that is cached on the drive electronics but not committed to media yet. Did I misunderstand your questions to Justin? It's quite possible as I've been switching between 5 different systems I'm working on today and I'm sure that things didn't committed to &my& media before things were wiped as switched from one KDE desktop to another..... To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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