From users-return-27711-apmail-activemq-users-archive=activemq.apache.org@activemq.apache.org Wed Jun 1 23:20:10 2011 Return-Path: X-Original-To: apmail-activemq-users-archive@www.apache.org Delivered-To: apmail-activemq-users-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 878AF67D8 for ; Wed, 1 Jun 2011 23:20:10 +0000 (UTC) Received: (qmail 81453 invoked by uid 500); 1 Jun 2011 23:20:10 -0000 Delivered-To: apmail-activemq-users-archive@activemq.apache.org Received: (qmail 81386 invoked by uid 500); 1 Jun 2011 23:20:10 -0000 Mailing-List: contact users-help@activemq.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: users@activemq.apache.org Delivered-To: mailing list users@activemq.apache.org Received: (qmail 81378 invoked by uid 99); 1 Jun 2011 23:20:10 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 01 Jun 2011 23:20:10 +0000 X-ASF-Spam-Status: No, hits=-0.7 required=5.0 tests=FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,RFC_ABUSE_POST,SPF_PASS,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of tarkasteve@gmail.com designates 209.85.215.43 as permitted sender) Received: from [209.85.215.43] (HELO mail-ew0-f43.google.com) (209.85.215.43) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 01 Jun 2011 23:20:04 +0000 Received: by ewy20 with SMTP id 20so154104ewy.2 for ; Wed, 01 Jun 2011 16:19:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:from:date :message-id:subject:to:content-type; bh=8NXAiv4Caz4o7f+BM3DRglM6tPrUccVsLPbjTv5y8Xo=; b=YAOibGfDKfSII8cDxWd231IKnqljEVb4Tq06CRJ5NLozoxItFF5tLbIojgJzBSkFXH pw7UiVfT23z/aoJkXLeYJ5HoJBLwHkPYlEwX4LtmLilAnjmHfXceFT4g5ouCvgQsguKx whh6QNi008iYsBO+BIy1OdVI4XYrWFdWuCqOk= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :content-type; b=UA3BHeRb383HHtMjuVKPwoIj0eHl+vviS4sDok8dF4YwlDFq77wpSTgZojb2JlsyaU 93usyOjR2Ek05MpvtDZMaKq8U7txrwOwefIz8iMkgEpAssAZL3bzsF7IugNwjQygUjnB 6pY92Cip+U5BLnqqR+TXl61C8GVVef1eG5Vrk= Received: by 10.14.9.72 with SMTP id 48mr23252ees.113.1306970383167; Wed, 01 Jun 2011 16:19:43 -0700 (PDT) MIME-Version: 1.0 Received: by 10.14.45.70 with HTTP; Wed, 1 Jun 2011 16:19:23 -0700 (PDT) In-Reply-To: References: From: Steve Smith Date: Thu, 2 Jun 2011 09:19:23 +1000 Message-ID: Subject: Re: KahaDB and backups To: users@activemq.apache.org Content-Type: text/plain; charset=ISO-8859-1 On 1 June 2011 19:50, Gary Tully wrote: > yes, a restored backup would be recoverable. > > In creating a backup, there may be an issue with the lock file, or > with an inuse journal file. The lock file is not important but you > would want the latest journal files. > > Linux will allow you to freeze a filesystem, I guess other os's have > similar support. > http://rwmj.wordpress.com/2010/06/09/freezing-filesystems/ > > We may want to introduce a way to have activemq freeze the journal, > block reads/writes and release open journal and index files for OS's > that don't have freeze support. Thanks Gary. Based on what you said I'm not sure that fsfreeze will guarantee a consistent journal by itself unless the journal is updated in a single atomic write. Is this the case? A user-space KahaDB snapshotting tool would certainly be useful regardless. Cheers, Steve