Standard PGD architecture
=========================

Using core PGD capabilites, the standard architecture configures the
three nodes in a multi-master replication configuration. That is, each
node operates as a master node and logically replicates its data to the
other nodes. While PGD is capable of handling conflicts between data
changes on nodes, the Essential standard architecture uses PGD’s
integrated connection manager to ensure that all writes are directed to
a single node, the write leader. Conflicts are avoided by allowing that
singular leader to handle all updates to the data. Changes are then
replicated to the other nodes in the cluster.

If the write leader fails, the remaining nodes in the cluster will elect
a new write leader, and the connection managers in those nodes then
failover to send writes to the new leader. When the failed node comes
back online, it rejoins the cluster and begins replicating data from the
new write leader.

The Essential standard architecture was created to be easy to deploy and
manage, based on user experience. Unlike other high availability
solutions, because Essential is built on PGD, moving to a more complex
architecture is simple and straightforward. Move to Expanded PGD, and
then add new data groups to the cluster as needed.

See :ref:`Manually deploying PGD Essential standard architecture <Manually deploying PGD Essential standard architecture>`  for more information on how to configure the standard
architecture.

.. toctree::
  :maxdepth: 5

  how_to--essential-how-to--architectures--standard--manually-deploying-standard