---------- Forwarded message ---------- From: Jacob Broido <<a href="mailto:jacob.broido@gmail.com">jacob.broido@gmail.com</a>> Date: Aug 24, 2005 7:00 PM Subject: Re: [dm-devel] cow snapshot on cloop device To: Kevin Corry <<a href="mailto:kevcorry@us.ibm.com">kevcorry@us.ibm.com</a>> I am using dmsetup directly. and I do the following: 1) Create an empty file that will be used as cow backing storage 2) losetup the backing file to /dev/loop0 3) create a snapshot of main root_device on /dev/loop0 4) mount the cow snapshot Here is the info you requested: The kernel is a - <a href="http://2.6.11.10" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">2.6.11.10</a> + xen patch. ======================================================= / # dmsetup ls root_master (253, 0) root_cow0 (253, 1) / # dmsetup table root_master: 0 4096128 linear 240:0 0 root_cow0: 0 4096128 snapshot 253:0 7:0 P 8 / # cat /proc/partitions major minor #blocks name 7 0 loop0 8 0 sda 8 1 sda1 8 2 sda2 8 3 sda3 240 0 cloop0 252 0 dm-0 253 1 dm-1 / # cat /proc/mounts rootfs / rootfs rw 0 0 /dev/root.old / ext2 rw 0 0 /proc /proc proc rw,noadirtime 0 0 /sys /sys sysfs rw 0 0 /dev/hdc /cdrom iso9660 ro 0 0 /ramdisk /ramdisk tmpfs rw 0 0 /dev/mapper/root_cow0 /cow ext2 rw.noatime 0 0 ====================================================<div> <div>On 8/24/05, Kevin Corry <<a href="mailto:kevcorry@us.ibm.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)"> kevcorry@us.ibm.com</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">On Wed August 24 2005 11:35 am, Jacob Broido wrote: > Hi, > I am trying to set a cow snapshot on a cloop device. > I managed to create a snapshot and mount it as read/write, but it appears > that the data inside the /cloop appears invalid: > > Binary executables appear to be invalid, I perfomed diff between files on > snapshotted /dev/cloop, and the same files accessed directly through cloop. > > The files were diffrent, > anyone has idea as to what can be the reason for this? Are you using LVM, EVMS, or dmsetup to create your snapshot? Please send in the output from "dmsetup ls" and "dmsetup table", as well as the contents of /proc/partitions and /proc/mounts, after you have activated and mounted your snapshot. -- Kevin Corry <a href="mailto:kevcorry@us.ibm.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">kevcorry@us.ibm.com</a> <a href="http://www.ibm.com/linux/" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)"> http://www.ibm.com/linux/</a> <a href="http://evms.sourceforge.net/" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">http://evms.sourceforge.net/</a> </blockquote> </div> </div><div>-- Not gonna be king of the world if you're slave to the grind - Skid Row </div> -- Not gonna be king of the world if you're slave to the grind - Skid Row