---
title: High Availability
slug: reference-guide-3-0-0/high-availability
description: Learn about the components and configurations of a Single Connect platform, featuring controller and controlled units across different regions. Discover the two types of clusters for the watchdog mechanism and the role of master and member instances in ea
docTags: 
createdAt: 2022-08-02T17:53:36.000Z
---

A fully deployed Single Connect platform includes controller units and controlled units in different regions. All these instances are independent of each other. Each region has its own master that runs SAPM and LDAP jobs.


There are two types of clusters for the watchdog mechanism:

-
  Watchdogs running in an environment without the Controller unit.
-
  Watchdogs running in an environment with the Controller unit.


Each environment consists of master and member instances.  The Master instance runs extra jobs related to SAPM and LDAP management.  A parameter defined in the Single Connect database determines which instance becomes the master, and can be changed if needed.