From owner-freebsd-fs@FreeBSD.ORG Mon May 17 10:49:35 2004 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 29A4016A4CE for ; Mon, 17 May 2004 10:49:35 -0700 (PDT) Received: from avgw.bjut.edu.cn (avgw.bjut.edu.cn [202.112.78.85]) by mx1.FreeBSD.org (Postfix) with SMTP id D7EC143D49 for ; Mon, 17 May 2004 10:49:33 -0700 (PDT) (envelope-from delphij@frontfree.net) Received: from beastie.frontfree.net ([218.107.145.7]) by avgw.bjut.edu.cn (SAVSMTP 3.1.5.43) with SMTP id M2004051801483107218 for ; Tue, 18 May 2004 01:48:31 +0800 Received: from localhost (localhost [127.0.0.1]) by beastie.frontfree.net (Postfix) with ESMTP id 9C8B611867; Tue, 18 May 2004 01:48:37 +0800 (CST) Received: from beastie.frontfree.net ([127.0.0.1]) by localhost (beastie.frontfree.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 00749-06; Tue, 18 May 2004 01:48:37 +0800 (CST) Received: by beastie.frontfree.net (Postfix, from userid 1001) id 4EE0F11634; Tue, 18 May 2004 01:48:36 +0800 (CST) Date: Tue, 18 May 2004 01:48:36 +0800 From: Xin LI To: Mikhail Teterin Message-ID: <20040517174836.GA983@frontfree.net> References: <200405171318.15200@misha-mx.virtual-estates.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="envbJBWh7q8WU6mo" Content-Disposition: inline In-Reply-To: <200405171318.15200@misha-mx.virtual-estates.net> User-Agent: Mutt/1.4.2.1i X-GPG-key-ID/Fingerprint: 0xCAEEB8C0 / 43B8 B703 B8DD 0231 B333 DC28 39FB 93A0 CAEE B8C0 X-GPG-Public-Key: http://www.delphij.net/delphij.asc X-Operating-System: FreeBSD beastie.frontfree.net 5.2-CURRENT FreeBSD 5.2-CURRENT #33: Mon Apr 26 15:10:21 CST 2004 delphij@beastie.frontfree.net:/usr/obj/usr/src/sys/BEASTIE i386 X-URL: http://www.delphij.net X-By: delphij@beastie.frontfree.net X-Location: Beijing, China X-Virus-Scanned: by amavisd-new at frontfree.net cc: freebsd-fs@freebsd.org Subject: Re: QMail and SoftUpdates X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 17 May 2004 17:49:35 -0000 --envbJBWh7q8WU6mo Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, May 17, 2004 at 01:18:15PM -0400, Mikhail Teterin wrote: > The link at >=20 > http://cr.yp.to/qmail/faq/reliability.html#filesystems >=20 > claims, using SoftUpdates for mailqueue is dangerous. Is that still > true? Thanks! Yes, it is dangerous. Same is true for any journalling file systems, which essentially does the same thing: delayed write of data/metadata. Delayed write will make it possible for the Operating System to group several writes together and write them once, or at least, in a better order in order to improve performance. However, for the mail case, once it responds "250", then the remote peer is allowed to remove the message from its queue. If the system crashes, and the data was not written into disk, then your message is lost. Mounting your mailqueue slice with -noatime is a good idea, too. Please note that disabling SoftUpdates will drastically decrease write performance on that slice. Of course, if your system often encounter crash or power failure, it will be a good idea to disable it. Cheers, --=20 Xin LI http://www.delphij.net/ See complete headers for GPG key and other information. --envbJBWh7q8WU6mo Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFAqPr0OfuToMruuMARAsqkAKCEOVLZKluaKhJS2c+LAssL5IbLkACcCvkt Xsois5bq9/IPn0RUrqUm5T4= =dbZD -----END PGP SIGNATURE----- --envbJBWh7q8WU6mo--