From owner-freebsd-questions@FreeBSD.ORG Thu Dec 6 19:20:15 2007 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2AD3716A469 for ; Thu, 6 Dec 2007 19:20:15 +0000 (UTC) (envelope-from peter.schuller@infidyne.com) Received: from smtp.infidyne.com (ds9.infidyne.com [88.80.6.206]) by mx1.freebsd.org (Postfix) with ESMTP id DE2B213C4F5 for ; Thu, 6 Dec 2007 19:20:13 +0000 (UTC) (envelope-from peter.schuller@infidyne.com) Received: from c-5416e555.03-51-73746f3.cust.bredbandsbolaget.se (c-5416e555.03-51-73746f3.cust.bredbandsbolaget.se [85.229.22.84]) by smtp.infidyne.com (Postfix) with ESMTP id 251AE7269C; Thu, 6 Dec 2007 20:20:12 +0100 (CET) From: Peter Schuller To: freebsd-questions@freebsd.org Date: Thu, 6 Dec 2007 20:22:28 +0100 User-Agent: KMail/1.9.7 References: <4758180C.4060208@livedatagroup.com> <47581D82.5000907@chrononomicon.com> <47581E5E.5080803@livedatagroup.com> In-Reply-To: <47581E5E.5080803@livedatagroup.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1619892.Zb4A5lHcYH"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200712062022.36783.peter.schuller@infidyne.com> Cc: Randy Ramsdell Subject: Re: Freebsd filesystem ( hard reboot ) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 06 Dec 2007 19:20:15 -0000 --nextPart1619892.Zb4A5lHcYH Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline > Well any number of things, but the most recent was a prolonged power > outage. It is important to differentiate between expected fsck activity and=20 unexpected. If you are running without write caching turned on (which is the default), = a=20 power outtage will constitute a crash from which a file system cannot=20 guarantee to recover unless it takes measure to punch through the write cac= he=20 at appropriate moments. If you machine shutdown softly as a result of the UPS communicating that po= wer=20 was running out, you "should" not have to fsck (barring other issues in the= =20 past). fsck need in these cases would indicate a software bug, or a hardwar= e=20 problem. If on the other hand your machine just lost power when the UPS finally died= ,=20 you are relying on luck for recovery if you're on ufs/reiserfs/xfs/etc. Som= e=20 environments will correctly handle this (e.g., ZFS), but most won't. The=20 problem being that drive write caching will prevent the file system from=20 guaranteeing ordering of certain critical operations that must be ordered i= n=20 order to guarantee successfull recovery to a consistent state. That said, you are not supposed to need to answer interactive questions on= =20 boot for all cases of expected inconsistencies. If you are getting prompts = as=20 a result of unexpected inconsistencies, that indicates *something* is wrong. =2D-=20 / Peter Schuller PGP userID: 0xE9758B7D or 'Peter Schuller ' Key retrieval: Send an E-Mail to getpgpkey@scode.org E-Mail: peter.schuller@infidyne.com Web: http://www.scode.org --nextPart1619892.Zb4A5lHcYH 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) iD8DBQBHWEv8DNor2+l1i30RAsy3AKDX5LWRsYBzElJ6IiGhhrRnf8F0ewCgtpU+ JawvlkNNXSLvs/wRjNfC4HA= =Lzpn -----END PGP SIGNATURE----- --nextPart1619892.Zb4A5lHcYH--