Article ID: 126377, created on Jul 31, 2015, last review on Jun 17, 2016

  • Applies to:
  • Virtuozzo
  • Virtuozzo containers for Linux
  • Virtuozzo hypervisor


After installing a new kernel, the hardware node does not boot and shows the error message:

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

There's no free space on /boot partition:

[root@vz ~]# df -h /boot
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1              99M   99M     0 100% /boot


The newly installed kernel failed to compile the initrd image and place it into /boot directory due to lack of disk space. The space is normally occupied by the previously installed kernels.


During the node start-up, press any key on GRUB initialization and choose the previous kernel to boot into.

  • Remove older kernels and free up space on /boot:

117245 How do I free up space on /boot partition?

  • Reinstall the most recent kernel:

If the server is running Virtuozzo:

# yum reinstall vzkernel

If it is a Virtuozzo containers installation:

# rpm -e vzkernel-2.6.32-042stab093.4.x86_64 vzkernel-firmware-2.6.32-042stab093.4.noarch vzmodules-2.6.32-042stab093.4.x86_64

# vzupdate -m batch install --core --loader-autoconfig

NOTE: The example above assumes that failed kernel is vzkernel-2.6.32-042stab093.4. Replace the package name with your particular kernel.

Search Words


Kernel panic - not syncing: VFS: Unable to mount roo fs on unknown-block(0, 0)


yum update

kernel panic not syncing

kernel panic-not syncing: VFS: unable to mount root fs on unknown block(0, 0)


new kernel

0dd5b9380c7d4884d77587f3eb0fa8ef 2897d76d56d2010f4e3a28f864d69223 a26b38f94253cdfbf1028d72cf3a498b d02f9caf3e11b191a38179103495106f e8e50b42231236b82df27684e7ec0beb

Email subscription for changes to this article
Save as PDF