From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mr Dash Four Subject: DM_snapshot_cow filesystem (dmsetup create snapshot) Date: Sat, 29 Oct 2011 12:19:13 +0100 Message-ID: <4EABE131.8010706@googlemail.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids As part of my livecd data structure dmsetup is used to create a snapshot containing xz-compressed root combined with copy-on-write ram-based overlay. The way as I understand it, the ram-based overlay contains only the "chunks" of data which is changed. Is there a way - in terms of a tool or by any other means - to look at this overlay to see what data has been changed exactly? I have tried, rather naively as it turned out, to mount the ram-based overlay but received "unknown filesystem type 'DM_snapshot_cow'" error message, which makes me thing that the data structure is unique somehow and private to the device mapper. One other thing - my dmsetup man page is from 2006 (created some 5 years ago) even though I am using the latest device-mapper package (1.02.63 I believe) and this man page does not contain any information on dmsetup create snapshot format, which is very annoying. Is there an updated version of the man page I could look at?