PGD Essential architectures
===========================

Choosing an architecture
------------------------

There are two supported architectures for PGD Essential. Essential
supports the two major use cases for replication: high availability and
disaster recovery. The architecture you choose depends on your use case.

They are standard and near/far.

Standard architecture - Ideal for a highly available single location
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The standard, or one-location, architecture is designed for a single
location that needs to be highly available. Built around three data
nodes, the Essential standard architecture ensures that data is
replicated across all three nodes and that, in the event of a failure,
the system can continue to operate without data loss.

Learn more about the :ref:`What is the PGD Essential Standard architecture <What is the PGD Essential Standard architecture>`  .

Near/far architecture - Ideal for disaster recovery
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The Near/Far architecture is designed for a single location that needs
to be reasonably highly available and needs to be able to recover from a
disaster. It does this by having a two-data-node cluster in the primary
location and a single data node in a secondary location.

Learn more about the :ref:`Near/far architecture - Ideal for disaster recovery <Near/far architecture - Ideal for disaster recovery>`  .

..  Note For multi-region deployments::
   For multi-region deployments, geo-distributed architectures are available in  `PGD Expanded <https://www.enterprisedb.com/docs/pgd/latest/expanded-how-to/architectures/>`_  . These architectures are designed for use cases that require data to be distributed across multiple regions or data centers. They provide advanced features such as conflict resolution, data distribution, and support for large-scale deployments. For more information on PGD Expanded, see the  `Expanded how-to <https://www.enterprisedb.com/docs/pgd/latest/expanded-how-to>`_  .

.. toctree::
  :maxdepth: 5

  how_to--essential-how-to--architectures--standard--index
  how_to--essential-how-to--architectures--near-far--index