Linux-HA
========

  Providing Open Source High-Availability Software
  for Linux and other Platforms since 1999

  The Linux-HA project maintains a set of building blocks
  for high availability cluster systems, including
    * a cluster messaging layer (heartbeat, see below),
    * a huge number of resource agents for a variety of applications,
    * a plumbing library and error reporting toolkit (aka cluster-glue)

      http://linux-ha.org/wiki/Main_Page
      http://en.wikipedia.org/wiki/Computer_cluster
      http://linux-ha.org/wiki/Heartbeat
      http://linux-ha.org/wiki/Resource_Agents
      http://linux-ha.org/wiki/Cluster_Glue


Historical note
===============

  Since up to release 2.1.4 the messaging layer (Heartbeat proper),
  the Local Resource Manager, "plumbing" infrastructure and STONITH
  (now known as Cluster Glue), the Resource Agents, and the Cluster
  Resource Manager (now Pacemaker) were all part of a single package
  named heartbeat, the name was often applied to the Linux-HA
  project as a whole.

  This generalization is no longer accurate, the name heartbeat
  should thus be used for the messaging layer exclusively. 


Heartbeat
=========

  Heartbeat is a daemon that provides cluster infrastructure (communication and
  membership) services to its clients. This allows clients to know about the
  presence (or disappearance!) of peer processes on other machines and to easily
  exchange messages with them.

  In order to be useful to users, the Heartbeat daemon needs to be combined with
  a cluster resource manager.  A cluster resource manager (CRM) has
  the task of starting and stopping the services (IP addresses, web
  servers, etc.) which the cluster will make highly available.

  Heartbeat still comes with an integrated primitive resource
  manager, which basically is just a shell script.  This is also
  referred to as "v1 style" or "haresources style" configuration.

  The haresources mode of operation is deprecated.
  If you miss it, please see
  http://www.planet-ha.org/#Configuring+Heartbeat+v1+Was+So+Simple

  Pacemaker is the preferred cluster resource manager for clusters
  based on the Heartbeat infrastructure layer.


Reference Documentation
=======================

  To get you started, for further information, reference documentation and
  setup recommendations, refer to
    http://linux-ha.org/wiki/Documentation
    http://clusterlabs.org/wiki/Documentation


Help and Support
================

  For community support, mailing lists, IRC channels, and
  other ways to report problems and get them solved, see
  http://linux-ha.org/wiki/Support


See Also
========

  Csync2
    an easy way to keep a bunch of infrequently updated files
    in sync over groups of nodes. http://oss.linbit.com/csync2/

  DRBD
    a nicely integrated (with Pacemaker) replication solution,
    you won't need shared disks to do HA-clustering.
    http://www.drbd.org

