.. _yocto-sstate:

Enable sstate cache 
===================

Sstate Cache Background [1]_
----------------------------

To speed up the build process, sstate provides a cache mechanism, where sstate files from server can be reused to avoid build from scratch if the producer and consumer of the sstate have the same environment. With perfect case, we can achieve more than 80% time decreasing.

Sstate Cache Server
-------------------

The default sstate files directory is sstate-cache under build dir. A mirror is available via sstate.karo-electronics.de.

In your build directory in ``conf/local.conf`` add those lines:

.. code-block:: text

   SSTATE_MIRRORS = " \
       file://.* http://sstate.karo-electronics.de/{yocto-release}/PATH \
   "

The special "PATH" suffix is important as it is automatically expanded to the correct value for native packages (which are split by the host distribution being used).

.. note:: Example values for ``{yocto-release}`` would be e.g. ``zeus``, ``gatesgarth``, ...


Verify Sstate is Working
------------------------

If sstate works, you can see something like:

.. code-block:: text

   ...
   Checking sstate mirror object availability
   ...
   SetScene Tasks

.. [1] More information in official documentation, `here <https://wiki.yoctoproject.org/wiki/Enable_sstate_cache>`_.