From owner-freebsd-stable@FreeBSD.ORG Fri Mar 28 06:38:10 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A17C1106566B; Fri, 28 Mar 2008 06:38:10 +0000 (UTC) (envelope-from m.seaman@infracaninophile.co.uk) Received: from smtp.infracaninophile.co.uk (gate6.infracaninophile.co.uk [IPv6:2001:8b0:151:1::1]) by mx1.freebsd.org (Postfix) with ESMTP id 164C28FC13; Fri, 28 Mar 2008 06:38:09 +0000 (UTC) (envelope-from m.seaman@infracaninophile.co.uk) Received: from happy-idiot-talk.infracaninophile.co.uk (localhost [IPv6:::1]) (authenticated bits=0) by smtp.infracaninophile.co.uk (8.14.2/8.14.2) with ESMTP id m2S6c4nP048859; Fri, 28 Mar 2008 06:38:04 GMT (envelope-from m.seaman@infracaninophile.co.uk) X-DKIM: Sendmail DKIM Filter v2.5.0 smtp.infracaninophile.co.uk m2S6c4nP048859 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=infracaninophile.co.uk; s=200708; t=1206686284; bh=yqry1OVXYE4Lhe lJWhmFvGmZamKBccFRk+AvzM2AESw=; h=Message-ID:Date:From:MIME-Version: To:CC:References:In-Reply-To:Content-Type:Cc:Content-Type:Date: From:In-Reply-To:Message-ID:Mime-Version:References:To; z=Message- ID:=20<47EC9245.6060200@infracaninophile.co.uk>|Date:=20Fri,=2028=2 0Mar=202008=2006:37:57=20+0000|From:=20Matthew=20Seaman=20|Organization:=20Infracaninophile|User-Agen t:=20Thunderbird=202.0.0.12=20(X11/20080310)|MIME-Version:=201.0|To :=20Ivan=20Voras=20|CC:=20freebsd-stable@freebs d.org|Subject:=20Re:=20Question=20about=20file=20system=20checks|Re ferences:=20<47EBA3AB.40307@infracaninophile.co.uk>=09=09<200803280029.08136.danny@ricin.c om>=20|In-Reply-To:=20|X-Enigmail-Version:=200.95.6|Content-Type:=20multipart/ signed=3B=20micalg=3Dpgp-sha256=3B=0D=0A=20protocol=3D"application/ pgp-signature"=3B=0D=0A=20boundary=3D"------------enig9078859072030 4798A660920"; b=pZIWUvctzrGzt7gMoE5fZCwrKqnbJEU59qtrXK7dLCL00BT8bhS 6+h4B4gGq9NkDlc/bW/ZKISj0PYrScHr9ZD2vxG+9KizHwZyGXZxyEj+V/koalBp2Fv VmeDdzhyJTa/SEbMMlOYdlfpaZY2x6U6IvPiQIff2txJoKCjC5TfA= Message-ID: <47EC9245.6060200@infracaninophile.co.uk> Date: Fri, 28 Mar 2008 06:37:57 +0000 From: Matthew Seaman Organization: Infracaninophile User-Agent: Thunderbird 2.0.0.12 (X11/20080310) MIME-Version: 1.0 To: Ivan Voras References: <47EBA3AB.40307@infracaninophile.co.uk> <200803280029.08136.danny@ricin.com> In-Reply-To: X-Enigmail-Version: 0.95.6 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enig90788590720304798A660920" X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-3.0 (smtp.infracaninophile.co.uk [IPv6:::1]); Fri, 28 Mar 2008 06:38:04 +0000 (GMT) X-Virus-Scanned: ClamAV 0.92.1/6433/Thu Mar 27 23:58:26 2008 on happy-idiot-talk.infracaninophile.co.uk X-Virus-Status: Clean X-Spam-Status: No, score=-3.0 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VERIFIED,NO_RELAYS autolearn=ham version=3.2.4 X-Spam-Checker-Version: SpamAssassin 3.2.4 (2008-01-01) on happy-idiot-talk.infracaninophile.co.uk Cc: freebsd-stable@freebsd.org Subject: Re: Question about file system checks X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Mar 2008 06:38:10 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig90788590720304798A660920 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Ivan Voras wrote: > Danny Pansters wrote: >=20 >> Generally I can say that with freebsd even if you pull the plug and=20 >> then let it reboot and do the automatical background fsck you'll=20 >> likely loose only that one file you might have been editing while (or = >> just before) you unplugged the box. >=20 > Stress testing I've done suggests otherwise :) I've literally repeatedl= y=20 > pulled the plug of a server in a controlled environment, and with a=20 > network logging of (a high load of) file system operations. My results = > show that UFS+SU and ZFS on FreeBSD loose *the most* files (and in case= =20 > of UFS+SU especially directories), than any of: jfs, xfs, reiser3 (on=20 > Linux 2.6.22) and NTFS (on Windows 2003 Server). ext3 is somewhat=20 > similar to UFS+SU, though about 30% better at not loosing files. >=20 > Some other notes from this proceeding: >=20 > 1. UFS+gjournal looses the least, but it's also the slowest. > 2. UFS+SU had no truncated files or files of unexpected length=20 > (apparently it just looses the file that would end up in this state) > 3. XFS and JFS end up with a *huge* number of files that are truncated = > or of unexpected length (40%-50%!) > 4. In no case has any of the above file systems gone completely=20 > corrupted or lost any of the files/directories not being updated. > 5. ZFS on FreeBSD was the fastest, in the sense of creating the most=20 > files during this benchmark (though speed was not the target for this=20 > benchmark so this is a low-quality observation), closely followed by JF= S=20 > and XFS. > 6. ZFS crashed the kernel at least once. >=20 Hmmm.... in many ways a corrupt or truncated file is a worse outcome than a completely missing file -- at least if the file has gone away you know you've got to do something to fix it. A damaged file could end up silently causing weird behavioural effects and (by the law of natural cussedness) it is almost bound not to be tracked down until the day after the last good copy on the backup tapes gets overwritten... How do the different filesystems compare if you total all lost, damaged or truncated files? Cheers, Matthew --=20 Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard Flat 3 PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate Kent, CT11 9PW --------------enig90788590720304798A660920 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.8 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEAREIAAYFAkfskkwACgkQ8Mjk52CukIwuyACfYZM+tJP/tKIm+xEsoZOpDLhe vwsAnRunRIGu37irlhehoZx4i6k6bjRQ =MA74 -----END PGP SIGNATURE----- --------------enig90788590720304798A660920--