From owner-freebsd-stable@FreeBSD.ORG Thu Mar 26 14:17:28 2009 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 2535B1065695 for ; Thu, 26 Mar 2009 14:17:28 +0000 (UTC) (envelope-from karl@denninger.net) Received: from FS.denninger.net (wsip-70-169-168-7.pn.at.cox.net [70.169.168.7]) by mx1.freebsd.org (Postfix) with ESMTP id D02BA8FC13 for ; Thu, 26 Mar 2009 14:17:27 +0000 (UTC) (envelope-from karl@denninger.net) Received: from [127.0.0.1] (localhost [127.0.0.1]) by FS.denninger.net (8.14.3/8.13.1) with SMTP id n2QEHQHU097205 for ; Thu, 26 Mar 2009 08:17:27 -0600 (CST) (envelope-from karl@denninger.net) Received: from [127.0.0.1] [192.168.1.40] by Spamblock-sys (LOCAL); Thu Mar 26 08:17:26 2009 Message-ID: <49CB8E74.9090508@denninger.net> Date: Thu, 26 Mar 2009 09:17:24 -0500 From: Karl Denninger User-Agent: Thunderbird 2.0.0.21 (Windows/20090302) MIME-Version: 1.0 To: Peter Schuller References: <3.0.1.32.20090326065337.00f081e0@sage-american.com> <3.0.1.32.20090325072137.00ee6b48@sage-american.com> <49C9E635.5010106@kkip.pl> <49C83673.3000604@aldan.algebra.com> <200903251820.54749.doconnor@gsoft.com.au> <200903251925.36108.doconnor@gsoft.com.au> <3.0.1.32.20090325072137.00ee6b48@sage-american.com> <3.0.1.32.20090326065337.00f081e0@sage-american.com> <3.0.1.32.20090326070807.00f081e0@sage-american.com> <200903261331.n2QDVd4b038485@lava.sentex.ca> <20090326140131.GA45201@hyperion.scode.org> In-Reply-To: <20090326140131.GA45201@hyperion.scode.org> Content-Type: multipart/mixed; boundary="------------010506020106090705000204" X-Antivirus: avast! (VPS 090325-0, 03/25/2009), Outbound message X-Antivirus-Status: Clean X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: "Jack L. Stone" , freebsd-stable@freebsd.org, fs@freebsd.org Subject: Re: support quality (Re: dump | restore fails: unknown tape headertype 1853384566) 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: Thu, 26 Mar 2009 14:17:28 -0000 This is a multi-part message in MIME format. --------------010506020106090705000204 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Peter Schuller wrote: >>> Yes, but it's for running a dump on a (L)ive FS and just spits out warnings >>> to that effect and has no effect on solving the problem(s). >>> >> Unless the filesystem is very busy, you will get your data backed up. >> If you have things like databases, I still would not trust >> snapshots. >> > > Uh. If backuping up a live database from a snapshot is not > trustworthy, either the snapshot facility is broken or the database is > broken (i.e., not crash-safe to begin with). > > That said there are plenty of other reasos to use proper dump tools > (data portability, confirming the ability to actually read all rows > from a table, using a more often exercised code path and perhaps less > likely to have edge case bugs, etc). > The issue with backing up a database live comes in when the filesystem where the database and transaction log files are DIFFERS. You can get into a pathological case in that instance. If the transaction log and database itself are both on the same snapshotted entity (that is, the snapshot is pulled at the same instant in time for both) what you get BETTER be restorable or your database's transaction log facility doesn't really do what it promises to do! -- -- Karl Denninger karl@denninger.net --------------010506020106090705000204--