1.2. Components

repmgr is a suite of open-source tools to manage replication and failover within a cluster of PostgreSQL servers. It supports and enhances PostgreSQL's built-in streaming replication, which provides a single read/write primary server and one or more read-only standbys containing near-real time copies of the primary server's database. It provides two main tools:

repmgr

A command-line tool used to perform administrative tasks such as:

  • setting up standby servers
  • promoting a standby server to primary
  • switching over primary and standby servers
  • displaying the status of servers in the replication cluster

repmgrd

A daemon which actively monitors servers in a replication cluster and performs the following tasks:

  • monitoring and recording replication performance
  • performing failover by detecting failure of the primary and promoting the most suitable standby server
  • provide notifications about events in the cluster to a user-defined script which can perform tasks such as sending alerts by email