Am 11.12.2011 11:45, schrieb Alex Bligh: > > > --On 8 December 2011 13:40:57 +0100 Kevin Wolf <kw...@redhat.com> wrote: > >>> qemu-img convert appears to support block devices as input, but not >>> as output. That is irritating, as when using qemu-img convert to >>> convert qcow to raw on a block partition, an intermediate file has >>> to be used, which slows things down and pointlessly uses disk space. >>> >>> The problem is that ftruncate() is being called on the output file >>> in order ensure it is sufficiently large, and this fails on >>> block devices. > ... >> >> Creating an image on a block device shouldn't even call raw_create(), >> but only hdev_create(), which doesn't try to truncate the device, but >> just uses lseek to make sure that it's large enough. >> >> Which qemu version are you using and what's your command line? > > I was testing on: > > amb@alex-test:~$ qemu-img --version > qemu-img version 0.12.3, Copyright (c) 2004-2008 Fabrice Bellard
That's the problem. It should work since 0.13. Kevin
