
df -hl
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1      2.0G  1.6G  393M  80% /
devtmpfs        7.4G     0  7.4G   0% /dev
tmpfs           7.4G     0  7.4G   0% /dev/shm
tmpfs           7.4G  176K  7.4G   1% /run
tmpfs           7.4G     0  7.4G   0% /sys/fs/cgroup
/dev/xvdb        37G   49M   35G   1% /mnt

cd /mnt

time virt-builder fedora-20
virt-builder: warning: cache /root/.cache/virt-builder: Unix.Unix_error(20, "mkdir", "/root/.cache/virt-builder")
virt-builder: disabling the cache
[   1.0] Downloading: http://libguestfs.org/download/builder/fedora-20.xz
#######################################################################   99.8%
[  91.0] Planning how to build this image
[  91.0] Uncompressing

/tmp/vbcache1c9535.txt: Success
/tmp/vbcache1c9535.txt: No space left on device
virt-builder: internal error: invalid argument: some threads failed, see earlier errors

