[Libguestfs] Virt-v2v conversion issue

Richard W.M. Jones rjones at redhat.com
Tue Oct 14 20:52:26 UTC 2014

On Tue, Oct 14, 2014 at 03:40:22PM +0000, VONDRA Alain wrote:
> Rich,
> I've followed your instructions to trace, but I am not very skilful with gdb, maybe I made a mistake :
> (1) As root do:
>   echo core.%p > /proc/sys/kernel/core_pattern  -> OK
> (2) Before running virt-v2v, do:
>   ulimited -c unlimited                 -> I think it's ulimit -c unlimited     -> -> OK
> and you should get a core.* file in the current directory when qemu-img segfaults.  Attach that file to gdb to get a stack trace:
>   gdb /usr/bin/qemu-img core.XYZ                -> Do I need to wait the crash becase I don't have any core ???

Yes, you have to wait for qemu-img to crash before there will be a
core dump.  If it's not crashing, then connect to qemu-img directly,
something like this:

  gdb /usr/bin/qemu-img `pidof qemu-img`

and run this command:

>   (gdb) t a a bt

to show the stack trace in all threads.

If qemu-img is consuming CPU then it's probably not hung.

I'm still interested to find out why fstrim didn't work.  Can
you run:

guestfish --ro -d unc-srv-qual03
><fs> run
><fs> part-list /dev/sda
><fs> part-list /dev/sdb
><fs> part-list /dev/sdc
><fs> part-list /dev/sdd

I'd be interested to see if the partitions are unaligned, which is the
only reason why fstrim should fail on NTFS.


Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-builder quickly builds VMs from scratch

More information about the Libguestfs mailing list