From owner-freebsd-hackers@FreeBSD.ORG Tue Oct 16 14:11:19 2007 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8254016A41A for ; Tue, 16 Oct 2007 14:11:19 +0000 (UTC) (envelope-from numisemis@yahoo.com) Received: from web36608.mail.mud.yahoo.com (web36608.mail.mud.yahoo.com [209.191.85.25]) by mx1.freebsd.org (Postfix) with SMTP id 5CE6A13C468 for ; Tue, 16 Oct 2007 14:11:19 +0000 (UTC) (envelope-from numisemis@yahoo.com) Received: (qmail 42458 invoked by uid 60001); 16 Oct 2007 13:44:37 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:Date:From:Subject:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-ID; b=b6l9ZYL2wHtq8yl/N1vf/7yTrBsycam3dJyQ1cQ2MPZa8Balfe961pGRmiGD02Qz9ELXC9OwmN9Om8T4CqAZt4eqanXPcPH7oJDGVa4U5FqnCHq6MtSKUhwGHvUAHtmqf161s724yH3CALwknpnf5YyZhrLiBkM2zZ1vneOCsy4=; X-YMail-OSG: 956Nq1sVM1l3majznyd5geEAuVJdc9DzG1MXG92mLnCqEB3tTGt3Yjj8kMvlPylTrr2_cmzlOkt7HU0TmpYKtaaJOZOwXAUIT167gbx2F_LspFIbiU5ey7HBNzp7ug-- Received: from [213.147.110.159] by web36608.mail.mud.yahoo.com via HTTP; Tue, 16 Oct 2007 06:44:36 PDT Date: Tue, 16 Oct 2007 06:44:36 -0700 (PDT) From: Simun Mikecin To: Jeremy Chadwick MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Message-ID: <5949.42099.qm@web36608.mail.mud.yahoo.com> X-Mailman-Approved-At: Tue, 16 Oct 2007 15:38:10 +0000 Cc: freebsd-hackers@freebsd.org Subject: Re: Filesystem snapshots dog slow X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 16 Oct 2007 14:11:19 -0000 Jeremy Chadwich wrote: >That said, for such setups, would you recommend *not* using snapshots? >If so, possibly we should consider removing the following code from >src/sbin/dump/main.c: >334 } else if (snapdump == 0) { >335 msg("WARNING: %s\n", >336 "should use -L when dumping live read-write " >337 "filesystems!"); >338 } else { Not using a snapshot for dump may produce inconsistent dump image if there was writing during dumping. Maybe it should say something like "should use -L when dumping live read-write filesystems for the result to be consistent (at the cost of speed)!". But that is too long :( >> FreeBSD 7 includes ZFS. Have you thought about using it? >I haven't. For starters, I keep seeing mails from users reporting data >corruption or kernel panics when using it. This doesn't mean ZFS is >"bad" (it's likely ZFS is exposing data corruption for them that's >occuring at a lower level (controller, disk, or RAM)), but it does keep >me from considering it a worthy alternative to UFS2 on production >systems at this time. And then there's this: >WARNING: ZFS is considered to be an experimental feature in FreeBSD. >This doesn't give admins "warm fuzzies". :-) I'm considering trying ZFS >on my home system (a ZFS filesystem atop a gstripe(8) pair), where I >also perform nightly backups using dump, but there's a part of me which >is asking "just how important is your data? What if ZFS breaks in the >middle of you using dump(8) on it? What then?" One of great things about ZFS is that you can forget about things like gstripe(8) or dump(8). You only need two commands: zpool and zfs. ZFS is not just a filesystem, it's also a logical volume management tool. ZFS on FreeBSD is considered experimental since it is very new. But from experience so far with it, only a few glitches do still exist: 1) root on ZFS is possible, but it could give you more problems then it solves (for now, it's best to have a small, say 512MB root filesystem running UFS, but everything else on ZFS). 2) using a zvol on ZFS for swap can cause a panic 3) using ZFS on FreeBSD/i386 can cause a panic (I suggest using UFS+gjournal instead of ZFS on FreeBSD/i386) Personally, I would choose ZFS on FreeBSD/amd64 production machine. ____________________________________________________________________________________ Be a better Globetrotter. Get better travel answers from someone who knows. Yahoo! Answers - Check it out. http://answers.yahoo.com/dir/?link=list&sid=396545469