Date: Tue, 18 May 2004 01:48:36 +0800 From: Xin LI <delphij@frontfree.net> To: Mikhail Teterin <mi+mx@aldan.algebra.com> Cc: freebsd-fs@freebsd.org Subject: Re: QMail and SoftUpdates Message-ID: <20040517174836.GA983@frontfree.net> In-Reply-To: <200405171318.15200@misha-mx.virtual-estates.net> References: <200405171318.15200@misha-mx.virtual-estates.net>
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--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 <delphij frontfree net> 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--
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