From owner-freebsd-stable@FreeBSD.ORG Tue Oct 28 19:20:05 2014 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id B18F54BF for ; Tue, 28 Oct 2014 19:20:05 +0000 (UTC) Received: from mail-wi0-x235.google.com (mail-wi0-x235.google.com [IPv6:2a00:1450:400c:c05::235]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 438FB9BB for ; Tue, 28 Oct 2014 19:20:05 +0000 (UTC) Received: by mail-wi0-f181.google.com with SMTP id n3so2647142wiv.8 for ; Tue, 28 Oct 2014 12:20:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=/iX7ZuCDKcR8dul11lB+WuDkApq5OaUbI0YWLIChetk=; b=SSQLMVW6tWQDO96F4n+iSiWpNNtSxGyjyIu9tpNbhP4HYt9EL4MKm55tD756zeBs5V 31L8SviCyaDNRa1ixIuUIxZDqAA0fGg7nQXreNx5WI0W2vWjKRI0XkYI8+r3ZCybJqOu ntklIDLCysecnrlIU9XbFm7CL9jXNkPVeVilBd2u+PQLWdp7L9Y4nRPTZ9Jg2b2fl+qP lJ8XkJ9uMJTKWk0WLFd965nyX99jn58s/1yiswJhN8e6ks1XrwH0P2bd+ybD5xR15ty4 NpFx0ImDpeD+nAPWwT8it83McZYYz+POz+KMCXEZ6LHwGnCoJjWKXygGDsGDnQ0oNAQd C5pw== MIME-Version: 1.0 X-Received: by 10.194.216.162 with SMTP id or2mr6847303wjc.68.1414524002044; Tue, 28 Oct 2014 12:20:02 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.216.106.136 with HTTP; Tue, 28 Oct 2014 12:20:01 -0700 (PDT) In-Reply-To: References: <6978A7BF-3CB7-4088-904D-5A60D755A04C@gmail.com> <20141025113846.GY1235@albert.catwhisker.org> <6bb4cda435fb420fb663fa1d47b85a08@ultimatedns.net> Date: Tue, 28 Oct 2014 12:20:01 -0700 X-Google-Sender-Auth: 61AubFvqaS5UeO05OI452K-Jh0Q Message-ID: Subject: Re: Dump time issues From: Adrian Chadd To: Kevin Oberman Content-Type: text/plain; charset=UTF-8 Cc: freebsd-stable , Chris H X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 28 Oct 2014 19:20:05 -0000 On 27 October 2014 11:09, Kevin Oberman wrote: >> I'm aware of two issues with SU+J, one of which is annoying and the other > is worse. > 1. If the journal is not fully written on power fail or some other reason, > you may need to do a full fsck of the volume and the behavior of the system > until this is done can be very unpredictable. > 2. You can't safely snapshot the system. This is what 'dump -L' does. This > means that some files dumped from a live FS may not be consistent (not > good!) or, if '-L' is used, the system may well hang. > > While I love the fast fsck times (2 or 3 seconds) after a crash, I also > question the default. Still, it may be a preferred choice be used for very > large file systems where a full fsck would take a very long time as long as > the risks are understood. For these systems, ZFS might be a better choice. > These arguments do NOT favor it being the default, IMHO. If people can reproduce SU+J problems then please file bugs. There have been some fixes with the journal handling over the last year or so and I haven't had this problem on -HEAD any longer, but it doesn't mean it's there. -adrian