From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (mx1.redhat.com [172.16.48.31]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id k9GL7pWW004836 for ; Mon, 16 Oct 2006 17:07:51 -0400 Received: from ug-out-1314.google.com (ug-out-1314.google.com [66.249.92.174]) by mx1.redhat.com (8.12.11.20060308/8.12.11) with ESMTP id k9GL7oaD002561 for ; Mon, 16 Oct 2006 17:07:50 -0400 Received: by ug-out-1314.google.com with SMTP id 39so812321ugf for ; Mon, 16 Oct 2006 14:07:45 -0700 (PDT) Message-ID: <87f94c370610161407j6b98d0aam3bb45969ed12962d@mail.gmail.com> Date: Mon, 16 Oct 2006 17:07:44 -0400 From: "Greg Freemyer" Subject: Re: [linux-lvm] Using LVM snapshots for hourly backups In-Reply-To: <20061013102208.0D52312EE1@bluewhale.planbit.co.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <452F66EF.5010005@mogmail.net> <20061013102208.0D52312EE1@bluewhale.planbit.co.uk> Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: LVM general discussion and development On 10/13/06, Roger Lucas wrote: > Hi Nick, > > RSYNC is useful for this, but it works at the file level. If you had, for example, a 1GB e-mail file (e.g. Outlook PST) or a large > database file, and it was getting small changes every day (e.g. receiving a dozen 10KB e-mails => 120KB of changes), then RSYNC > would quickly eat up your disk space as each backup taken with RSYNC a complete new copy of the whole 1GB file. > > Cascaded LVM snapshots, on the other hand, would allow the just the changes within the files to be kept, dramatically reducing the > disk usage. > > I'm sure that you know this already, but it was worth explicitly stating the difference between RSYCN and LVM snapshots in case > someone reading the list wasn't as sure. > > BR, > > Roger For now, you may want to checkout rdiff-backup. It uses rsync like functionality to find deltas in your files and then it only backs up the deltas. IIRC, it actually keeps a current copy of your file, plus a series of deltas that let you get to older versions. Greg -- Greg Freemyer The Norcross Group Forensics for the 21st Century