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I want to build HA Postgres cluster with automatic redirection of session to another node like oracle RAC with no SPOF.
This can be achieved by the EnterpriseDB's Failover manager. EDB Postgres Failover Manager (EFM) is a high-availability module from EnterpriseDB that enables a Postgres Master node to automatically failover to a Standby node in the event of a software or hardware failure on the Master.
My requirement is of Active/Active cluster with connection pooling and load balancing with middleware pgbouncer.
For Active/Active cluster you can use the Replication Server(xDB) provided by EnterpriseDB. It works but the only downside is in case of failover you need to reconfigure MMR setup from where the next Replication Server will take charge on the server. Because Replication Server is based on Logical replication slots and slots information never replicated to slaves/standbys. You can verify by running queries on slave/standby "pg_replication_slots" view. Currently, automation/HA are not supported in Replication Server. In any case, manual start and reconfigure of replication setup is required.
Also please suggest if i use shared storage architecture with data on shared mount point.
what are its pros/cons wrt. HA and postrges
As per your architecture, you are looking for no service outage, it may not be a solution but you can try OS Level HA Active/Passive software.
Please check the attachement for the detailed discussion of the HA and the EnterpriseDB's available tools for the same. The purpose of the attached paper is to provide a systematic overview of the principal Postgres clustering types that EDB recommends to help a customer achieve enhanced availability and manageability.
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