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Line 1: − It turns out that it is possible to merge down the persistent overlay into the base image, if you have access to another OS installation and sufficient disk space.+ − : Another OS installation is optional. (See [[LiveOS image#Image recompression and overlay refreshment]].) − : Thanks for demonstrating this technique. --[[User:FGrose|FGrose]] 01:21, 20 August 2012 (EDT) − I like that result better than just having to increase the overlay size without bounds. − − Tested and working on a Fedora 17 x86_64 Live image installed via livecd-iso-to-disk to a USB stick, all commands as root. You will need disk space sufficient for the uncompressed size of the root filesystem, 4 GB in the case of Fedora 17. I assume only one image and one user on the machine. − − Step 1: Get access to read-write base image, note that I got loop2 and loop3 here, YMMV. − <nowiki>mkdir squashfs − mount -o loop /run/media/*/LIVE/LiveOS/squashfs.img squashfs/ − cp squashfs/LiveOS/ext3fs.img .</nowiki> − − Step 2: Set up loopback and device mapper devices for persistent overlay, base device mapper and snapshot. − <nowiki>losetup -f ext3fs.img − losetup -f /run/media/*/LIVE/LiveOS/overlay-* − echo 0 $(blockdev --getsize /dev/loop2) linear /dev/loop2 0 |dmsetup create orig − echo 0 $(blockdev --getsize /dev/mapper/orig) snapshot /dev/mapper/orig /dev/loop3 p 8 | dmsetup create top</nowiki> − − Step 3: Stop the snapshot device and merge the snapshot with the base − <nowiki>dmsetup suspend top − echo 0 $(blockdev --getsize /dev/loop2) snapshot-merge /dev/loop2 /dev/loop3 p 8 | dmsetup create mergeomatic && dmsetup status mergeomatic</nowiki> − − Step 4: Wait for merge to complete. When the status report on mergeomatic reports allocated blocks equal to the metadata blocks, the merge is finished. − dmsetup status − − Step 5: Remove the merge target. − dmsetup remove mergeomatic − − Step 6: Set the top device to no snapshot, and inspect the filesystem for results, if desired. − <nowiki>echo 0 $(blockdev --getsize /dev/loop2) linear /dev/loop2 0 | dmsetup load top − dmsetup resume top − mkdir root − mount /dev/mapper/top root − cd root − chroot .</nowiki> − − Step 7: Clean up. − <nowiki>cd .. − umount root − dmsetup remove top − dmsetup remove orig − losetup -d /dev/loop2 − losetup -d /dev/loop3 − umount squashfs/</nowiki> − − Step 8: Copy the root filesystem image back into the squashfs image, you may need -noappend − <nowiki>mkdir LiveOS − mv ext3fs.img LiveOS − rm /run/media/*/LIVE/LiveOS/squashfs.img − mksquashfs LiveOS /run/media/*/LIVE/LiveOS/squashfs.img -keep-as-directory</nowiki> − − Sources: <br> − *http://smorgasbord.gavagai.nl/2010/03/online-merging-of-cow-volumes-with-dm-snapshot <br> − *http://www.kernel.org/doc/Documentation/device-mapper/snapshot.txt<br> − *http://linuxgazette.net/114/kapil.html<br> − − --[[User:Andrew Gilmore|Andrew Gilmore]] − − : I have copied most of this Fedora content to the Fedoraproject wiki, at [[fedora:LiveOS image]]. --[[User:FGrose|FGrose]] 23:38, 20 August 2012 (EDT)
Replaced content with "Previous content for this page is now at the Fedora Project wiki, fedora:Talk:LiveOS image. --~~~~"
Previous content for this page is now at the Fedora Project wiki, [[fedora:Talk:LiveOS image]]. --[[User:FGrose|FGrose]] 22:15, 21 August 2012 (EDT)