Hi!
Your snippet shows that the disks are equal, and the memory is not...
This is not an issue anyway, ganeti is able to create instance disks even on unequal disks... Can you please tell us how disk creation fails so it's easier to see what the real issue is? You can also contact the ganeti team on its mailing list (ganeti@googlegroups.com) and even join it (see
http://code.google.com/p/ganeti), for help and suggestions
Thanks,
Guido