From owner-freebsd-stable@FreeBSD.ORG Tue Oct 28 19:52:54 2014 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 60BF0C75; Tue, 28 Oct 2014 19:52:54 +0000 (UTC) Received: from mail-ie0-x22c.google.com (mail-ie0-x22c.google.com [IPv6:2607:f8b0:4001:c03::22c]) (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 17EFFE3F; Tue, 28 Oct 2014 19:52:54 +0000 (UTC) Received: by mail-ie0-f172.google.com with SMTP id rl12so1487811iec.17 for ; Tue, 28 Oct 2014 12:52:53 -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=G7VvvGQriRVuQYUiQfdVUtqVcQFtGuU6J24FllvAYMs=; b=Ic1i38c4/yL2ujKoNhXu878ASqgXrGS0vKwWlFCAzIqGlEXA4+AhjakE5qn/dsUIdc 0KE6DZVPoDO97tP/CJDEnR34jyc+IlmN82jjMSHxnTt6KB63pk4c+uyl892cl0P8F8Pz KATElkU5xhiqLCOquqkZ+hR694NH1/FRIYrqlXZ6qwV8tvWf/qtmGKVZUIBtk1K7mN4y GavK42WqqwAZmtNe2tWtJKgq8Sne3oaS0zRzppRD4hVhNYkCfrQlG23uBgVXtsBImxmU pCB0UxvaPc8Om2+bKNuBFq4qi6JFS4p7i2dOXq8uqAANqirtCxmoa3Ju5i7PQcI/a3ow uhCg== MIME-Version: 1.0 X-Received: by 10.50.142.71 with SMTP id ru7mr32462818igb.32.1414525973398; Tue, 28 Oct 2014 12:52:53 -0700 (PDT) Sender: kob6558@gmail.com Received: by 10.107.11.152 with HTTP; Tue, 28 Oct 2014 12:52:53 -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 12:52:53 -0700 X-Google-Sender-Auth: 3fMZJlAKsZyBTFiQQEfNMsE4T_k Message-ID: Subject: Re: Dump time issues From: Kevin Oberman To: Adrian Chadd Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 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 19:52:54 -0000 On Tue, Oct 28, 2014 at 12:20 PM, Adrian Chadd wrote: > 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 > The snapshot issue has been submitted to bugzilla several times. One is 173301. If it has been fixed, great, but the bug has not been touched and I have not seen any reports of it being fixed. Guess I could try a "dump -L" on my server and see, but I would hate to see it down for very long if the problem has not been fixed in 10.1-RC3-p1. Ihave no system running HEAD ATM, so If any fix has not made it to 10.1, I will not be able to test. The first issue is probably not a bug, but just very unlucky timing and does not damage the file system.I have seen many reports with the standard answer of "run a full fsck" which seems to fix it.