Hi, On Thursday, 26 December 2019 11:27:46 CET gilles2.lebris(a)laposte.net wrote: The extract of the failure is: [...] supermin: waiting another 1024000000 ns for /sys/block/sdb/dev to appear This usually means your kernel doesn't support virtio, or supermin was unable to load some kernel modules (see module loading messages above). supermin: waiting another 2048000000 ns for /sys/block/sdb/dev to appear supermin: waiting another 4096000000 ns for /sys/block/sdb/dev to appear supermin: waiting another 8192000000 ns for /sys/block/sdb/dev to appear supermin: waiting another 16384000000 ns for /sys/block/sdb/dev to appear supermin: waiting another 32768000000 ns for /sys/block/sdb/dev to appear supermin: waiting another 65536000000 ns for /sys/block/sdb/dev to appear supermin: waiting another 131072000000 ns for /sys/block/sdb/dev to appear supermin: waiting another 262144000000 ns for /sys/block/sdb/dev to appear supermin: creating /dev/root as block special 1:0 supermin: mounting new root on /root [ 525.350726] EXT2-fs (ram0): error: can't find an ext2 filesystem on dev ram0. Your system seems to be RHEL/CentOS 7.7, however there is a different kernel installed: \x1b[2J[ 0.000000] Linux version 4.19-ovh-xxxx-std-ipv6-64 (kernel(a)kernel.ovh.net) (gcc version 6.3.0 20170516 (Debian 6.3.0-18+deb9u1)) #1038749 SMP Mon Dec 23 08:31:48 UTC 2019 It sounds like that kernel is broken, and it does not have virtio modules. Please report that to whoever supplied that kernel. If there is the stock RHEL/CentOS kernel available in /boot, you can explicitly use it: - wipe /var/tmp/.guestfs-0 - export the SUPERMIN_KERNEL environment variable to the full path of the RHEL/CentOS kernel, e.g. # export SUPERMIN_KERNEL=/boot/vmlinuz-etc... (see the supermin(1) man page for more details) - try running libguestfs-test-tool again -- Pino Toscano