On Wed, Dec 1, 2010 at 7:41 PM, Lukas Czerner <lczerner@xxxxxxxxxx> wrote: > Hi, all > > As Ted suggested on LPC I started to play with e2image to add support for > exporting images in QCOW2 format (http://en.wikipedia.org/wiki/Qcow2). The > advantage of this format is mainly that the resulting image is quite small > (because we write only the metadata blocks) and it is not sparse unlike > "sparse" image format. > > I am presenting you an initial parch, which works for me quite nicely, however > so far it did received just limited testing. Nevertheless you can try it simply > by invoking e2image with '-q' parameter like this: > > e2image -q /dev/sda1 myimage > > or you can add '-s' option so the file names are scrambled. To mount that qcow2 > image I usually use 'qemu-nbd': > > modprobe nbd max_part=8 > qemu-nbd --connect=/dev/nbd0 myimage > mount -o ro /dev/nbd0 /mnt/test/ > > However I have experienced some problems with qemu-nbd from time to time. Also > for some reason, when you mount the image read-write, you'll destroy it. So far > I was not able to figure out why (I did not tried at all to be honest), it may > be problem in my image format or even in qemu itself, so if you have any idea, > please let me know. > > QCOW2 format supports other neat features like compression, encryption and > snapshots. None of those feature are supported in this patch and the question > is, do we need it ? I can imagine for example snapshots to be useful for > roll-back changes made by e2fsck, but this is hardly problem of e2image itself. > > So, please look at the patch, try it and let me know what else you thing is > useful to implement, or what would you like to change. > Hi Lukas, This is very cool :-) My wish is to export next3/ext4 snapshots as qcow2 snapshots. I actually thought of implementing e2image -x <snapid> as a way to export a snapshot image, but using qcow2, file system can be exported with all of it's snapshots. It should be quite trivial since next3 snapshots contain a map of changed blocks and I suppose qcow2 snapshots should be the same. Now I only need to find the time to do it... Amir. > Anny comments appreciated. > > Thanks! > > -Lukas > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
