From owner-freebsd-fs Mon Mar 12 16: 9:28 2001 Delivered-To: freebsd-fs@freebsd.org Received: from fw.wintelcom.net (ns1.wintelcom.net [209.1.153.20]) by hub.freebsd.org (Postfix) with ESMTP id BC67337B71A; Mon, 12 Mar 2001 16:09:20 -0800 (PST) (envelope-from bright@fw.wintelcom.net) Received: (from bright@localhost) by fw.wintelcom.net (8.10.0/8.10.0) id f2D07he27097; Mon, 12 Mar 2001 16:07:43 -0800 (PST) Date: Mon, 12 Mar 2001 16:07:43 -0800 From: Alfred Perlstein To: Matthew Jacob Cc: "Justin T. Gibbs" , Soren Schmidt , Kevin Oberman , scsi@FreeBSD.ORG, fs@FreeBSD.ORG, dillon@FreeBSD.ORG Subject: Re: Disk I/O problem in 4.3-BETA Message-ID: <20010312160742.L18351@fw.wintelcom.net> References: <20010312154452.K18351@fw.wintelcom.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from mjacob@feral.com on Mon, Mar 12, 2001 at 03:53:10PM -0800 X-all-your-base: are belong to us. Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org * Matthew Jacob [010312 15:53] wrote: > > > 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..... Your previous paragraph "Well, if I understood your mail" is what I was looking for. Basically I was inquiring if the hardware could/would support a request to perform a write-through or not lie about the write completing for certain tagged writes. -- -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org] Daemon News Magazine in your snail-mail! http://magazine.daemonnews.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message