Re: [Libguestfs] virt-resize: ntfsresize: location outside device

On Sun, Sep 12, 2010 at 02:19:11PM -0400, sean darcy wrote: I think this is a bug in virt-resize's calculations of sector offsets. Can you run the program with LIBGUESTFS_DEBUG=1 virt-resize --debug [...other params...] and post the complete, unedited output in a new bug report @ https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&produc... Then I can take a closer look at it. This is also a (different) bug. For some reason I thought it was a good idea to look at the file size, rather than using guestfs_blockdev_getsize64 API. This bug is filed here: https://bugzilla.redhat.com/show_bug.cgi?id=633096 It's actually a lot more complex than it seems to do this manually, which I guess is why we wrote virt-resize. You can copy the data over easily; see the script at the end of this email. The hard part is that this simple-minded script puts the partitions in the wrong place and doesn't copy over the hidden bootloader which is stuffed somewhere between the boot sector and the first partition. So if you try the script, your new VM won't boot. If you really want to do it manually you can calculate where you need to start the first partition by running 'part-list' on the original VM image, eg: guestfish --ro -i XP.img <<EOF part-list /dev/sda EOF which will give you some output like: [0] = { part_num: 1 part_start: 1048576 part_end: 105906175 part_size: 104857600 } and then you take the 'part_start' value, which is in bytes, divide by 512 (bytes per sector) and use it to manually create the target partition. So instead of 'part-disk' in the non-working script below, you need to use, say: part-init /dev/sdb mbr part-add /dev/sdb primary 2048 -64 (which creates a partition from byte 1048576 up to 64 sectors from the end of the disk). You have to copy over the bootloader data, eg: copy-size /dev/sda /dev/sdb 1048576 *before* the part-init and part-add commands, because that trashes the updated partition table (or you can repeat those commands). As you can see it's a big load of hassle even for this relatively simple case (a single partition) and just gets harder once you throw more partitions into the mix. Rich. ---------------------------------------------------------------------- # Non-working example script. qemu-img create --format=qcow2 XP-new.img 20G guestfish <<EOF # Add the existing image, read only, as /dev/sda. add-ro XP.img # Add the new image, writable, as /dev/sdb. add XP-new.img # Launch the appliance. run # Partition the new image, single partition over whole disk. part-disk /dev/sdb mbr # Copy the data across. dd /dev/sda1 /dev/sdb1 # Resize the target. ntfsresize /dev/sdb1 EOF -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://et.redhat.com/~rjones/virt-top