From owner-freebsd-current@FreeBSD.ORG Tue Aug 28 21:24:15 2007 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B6CA016A418; Tue, 28 Aug 2007 21:24:15 +0000 (UTC) (envelope-from max@love2party.net) Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.126.188]) by mx1.freebsd.org (Postfix) with ESMTP id 37DBA13C467; Tue, 28 Aug 2007 21:24:14 +0000 (UTC) (envelope-from max@love2party.net) Received: from dslb-088-066-017-000.pools.arcor-ip.net [88.66.17.0] (helo=amd64.laiers.local) by mrelayeu.kundenserver.de (node=mrelayeu8) with ESMTP (Nemesis), id 0ML31I-1IQ8Xf0nBz-0001J0; Tue, 28 Aug 2007 23:24:10 +0200 From: Max Laier Organization: FreeBSD To: freebsd-current@freebsd.org Date: Tue, 28 Aug 2007 23:23:56 +0200 User-Agent: KMail/1.9.7 References: <20070828211440.470805B3B@mail.bitblocks.com> In-Reply-To: <20070828211440.470805B3B@mail.bitblocks.com> X-Face: ,,8R(x[kmU]tKN@>gtH1yQE4aslGdu+2]; R]*pL,U>^H?)gW@49@wdJ`H<=?utf-8?q?=25=7D*=5FBD=0A=09U=5For=3D=5CmOZf764=26nYj=3DJYbR1PW0ud?=>|!~,,CPC.1-D$FG@0h3#'5"k{V]a~.<=?utf-8?q?mZ=7D44=23Se=7Em=0A=09Fe=7E=5C=5DX5B=5D=5Fxj?=(ykz9QKMw_l0C2AQ]}Ym8)fU MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart3085233.neSCxyxR4m"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200708282324.05834.max@love2party.net> X-Provags-ID: V01U2FsdGVkX18TR6WW72n0rJSuVCUVlrOVTK4IWhwl28mnsaL Hr9zB1ci5k6C3VE+RHujObFZ/QNshHnO1NUcPF5djhuxJUfJ1i bzG6Tsoyfagj6J4AkzoCT4eIL0qQZq/V3KcBICgVxI= Cc: Pawel Jakub Dawidek , Pascal Hofstee Subject: Re: ZFS kernel panic X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 28 Aug 2007 21:24:15 -0000 --nextPart3085233.neSCxyxR4m Content-Type: text/plain; charset="iso-8859-6" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Tuesday 28 August 2007, Bakul Shah wrote: > > > The simplest thing to do in case of a write error is to > > > simply ignore it. You *will* catch this problem when you try > > > to read this block. One step better is to do what you > > > suggest. > > > > You can't ignore write error, because application already assumed the > > write succeeded, which can lead to misbehaviour later. ZFS cannot yet > > handle write error, so it panics to preserve data consistency. This > > is the good reaction on ZFS side until skipping bad blocks is not > > implemented. > > If you ignore a write error, the effect is the same as if the > disk block was good on writing but went bad before the first > read. Seems to me this is better than panicing (but of > course not as good as finding an alternate block). This is complete nonsense! As you pointed out earlier zfs doesn't know=20 anything about the nature of the error. There is only one sensible way=20 to deal with a disk error - unless it is transient - and that is stopping=20 all (write) access to the drive. As you can't easily move a mounted=20 drive with opened files into read-only mode, a panic is the only way to=20 make sure. > AFAIK ZFS already uses redundancy for metadata so the > metadata consistency will be maintained. > > > > What happens now when you do use redundancy and there is a > > > write error while writing one of the copies? Does the system > > > panic or is this error ignored? > > > > Don't remember off hand, but component is probably marked as bad and > > vdev group goes to degraded state. You can simulate this easly with > > gnop(8). > > Thanks. It would be good to add some ioctl to allow failing > specific blocks on reads and/or writes. =2D-=20 /"\ Best regards, | mlaier@freebsd.org \ / Max Laier | ICQ #67774661 X http://pf4freebsd.love2party.net/ | mlaier@EFnet / \ ASCII Ribbon Campaign | Against HTML Mail and News --nextPart3085233.neSCxyxR4m Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQBG1JJ1XyyEoT62BG0RApDpAJ4rMr/fCBTJKVwACyZmoptRATPPOwCeMqDC 6JOLk+6u4/idt694tRaVepA= =uE5+ -----END PGP SIGNATURE----- --nextPart3085233.neSCxyxR4m--