Synnefo » snf-ganeti

- `socat <http://www.dest-unreach.org/socat/>`_, see :ref:`note

  <socat-note>` below

.. _socat-note:

.. note::

  Ganeti's import/export functionality uses ``socat`` with OpenSSL for

  transferring data between nodes. By default, OpenSSL 0.9.8 and above

  employ transparent compression of all data using zlib if supported by

  both sides of a connection. In cases where a lot of data is

  transferred, this can lead to an increased CPU usage. Additionally,

  Ganeti already compresses all data using ``gzip`` where it makes sense

  (for inter-cluster instance moves).

  To remedey this situation, patches implementing a new ``socat`` option

  for disabling OpenSSL compression have been contributed and will

  likely be included in the next feature release. Until then, users or

  distributions need to apply the patches on their own.

  Ganeti will use the option if it's detected by the ``configure``

  script; auto-detection can be disabled by explicitely passing

  ``--enable-socat-compress`` (use the option to disable compression) or

  ``--disable-socat-compress`` (don't use the option).

  The patches and more information can be found on

  http://www.dest-unreach.org/socat/contrib/socat-opensslcompress.html.