Re: Postgres HA

[Julyanto Sutandang <julyanto@xxxxxxxxx>]

Dear Dylan, 

Talking about High Availability, we should understand the basic concept of HA, it is avoiding SPOF (Single Point of Failure). When we use a Loadbalancer (LTM) and that load balancer is single, then you may get HA only for the PostgreSQL but there are another single point of failure, it is the LTM it self. In overall that  topology is not HA. 

The best configuration for HA i know is using Linux-HA to watch between 2 servers and doing failover VIP (Virtual IP) when Master is down or out of service. The best configuration for HA, Servers should be on the same site and uses direct cable connection to ensure dedicated private bandwidth and there are no Single Point of Failure. 

LinuxHA or pacemaker or corosync will do the Virtual IP swing over from master host to slave host and promote the replica database in slave host become master. 

There is no single point of failure. 

Julyanto SUTANDANG

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On Thu, Feb 23, 2017 at 5:58 AM, Dylan Luong <Dylan.Luong@xxxxxxxxxxxx> wrote:

Hi

 

I am a DBA at the University of South Australia. For PostgreSQL High Availability, we currently have setup a Master/Slave across two datacenters using PostgreSQL (WAL) streaming replication. We use an LTM (load balancer) server that sits between the application servers and the PostgreSQL server that directs connections to the Master (and the Slave if failover occurs). We also have watchdog processes on the PostgreSQL servers that polls the LTM to determine who is Master and perform automatic failover if required. I am looking at options to improve our high availability.

I would like to know how other organizations in different industries (other than education) setup High Availability on their PostgreSQL environments.

What  tools do you use. Are they commercial licensed products? How is the architecture setup and how do you do recovery of new slave.

Your information is greatly appreciated.

 

Regards

Dylan

 

Dylan Luong

Information Strategy & Technology Services

University of South Australia

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