Article ID: 117455, created on Sep 23, 2013, last review on Jun 17, 2016

  • Applies to:
  • Virtuozzo 6.0


After updating Parallels Cloud Server to 6.0-update4, it is not possible to create a new container or create OS template cache.

  1. The running kernel is 2.6.32-042stab078.x or below:

    ~# uname -a
    Linux pcs6 2.6.32-042stab076.5 #1 SMP Mon Mar 18 20:41:34 MSK 2013 x86_64 x86_64 x86_64 GNU/Linux
  2. The rest of the installation is up-to-date:

    ~# rpm -qa \*release*
    ~# rpm -qa vztt\* vzctl\* | sort
  3. OS template caching fails:

    ~# vzpkg create cache centos-6-x86_64
    Creating OS template cache for centos-6-x86_64 template
    Loaded plugins: rpm2vzrpm
    Cleaning repos: base0 base1 base2 base3
    Error: Failed to create ploop image /vz/tmp//vzpkg.QeW1kS/root.hds: 38
    Error: Cannot create ploop device
    Error: Failed to read ploop disk descriptor /vz/tmp//vzpkg.QeW1kS: -1
  4. Creating a new container fails too:

    ~# vzctl create 60 --ostemplate debian-6.0-x86_64
    Cached package set 'debian-6.0-x86_64' is not found, run create cache utility...
    Creating OS template cache for debian-6.0-x86_64 template
    Converting /vz/template/cache/debian-6.0-x86_64.plain.ploop.tar.lzrw to /vz/template/cache/debian-6.0-x86_64.plain.ploopv2.tar.lzrw
    Creating new format ploop...
    Error: Failed to create ploop image /vz/tmp//vzpkg.feYrXK/root.hds: 38
    Error: Failed to convert /vz/template/cache/debian-6.0-x86_64.plain.ploop.tar.lzrw to ploop v2 format


The update includes support of the new version of Ploop images, for better performance, stability of containers and this mode is forced to be used by default. However, it needs the support from the kernel side which is missing in the kernels below 2.6.32-042stab79.x.

This causes issues with creating a new container and caching of OS templates.


Install the updates to Parallels Cloud Server - the request PSBM-22393 is corrected by the hotfix 1 for PCS 6.0 update 4

~# yum update

Reboot the system to the latest kernel is also recommended.

Search Words

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38 Error: Failed to convert

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