[Pgpool-general] replication/failover feature in Master/Slavemode

[Daniel.Crespo at l-3com.com]

"failover_command" entry in pgpool.conf allows you to do whatever you need to do when pgpool detects a database node degeneration. In your case you would need to touch the file where PostgreSQL 9.0+ expects it (specified in "trigger_file" within recovery.conf). Take a look at how postgresql 9.0's built-in replication works, and then you'll know what to touch and where.

 

-Daniel

 

From: pgpool-general-bounces at pgfoundry.org [mailto:pgpool-general-bounces at pgfoundry.org] On Behalf Of Sandeep Thakkar
Sent: Thursday, January 27, 2011 3:50 AM
To: Sandeep Thakkar; Guillaume Lelarge
Cc: pgpool-general at pgfoundry.org
Subject: Re: [Pgpool-general] replication/failover feature in Master/Slavemode

 

I was just testing the pgpool with one primary and one standby on the same box. Hot Standby, Streaming replication, load balancing, all are working fine. But, I see that failover is not happening when I shut down my primary server. When I manually touch the trigger file, failover happens. I thought, pgpool will execute the fail over command on it's own. Am I doing anything wrong?

Here is my related settings in pgpool.conf:
failover_command = 'touch <path_to_trigger_file>


My recovery.conf in the data directory of standby contains these variables:
standby_mode
primary_conninfo
restore_command
trigger_file


Please help. 

 

 

________________________________

From: Sandeep Thakkar <sandeeptt at yahoo.com>
To: Guillaume Lelarge <guillaume at lelarge.info>
Cc: pgpool-general at pgfoundry.org
Sent: Fri, January 14, 2011 2:40:52 PM
Subject: Re: [Pgpool-general] replication/failover feature in Master/Slave mode

Thanks Guillaume. 

 

 

________________________________

From: Guillaume Lelarge <guillaume at lelarge.info>
To: Sandeep Thakkar <sandeeptt at yahoo.com>
Cc: pgpool-general at pgfoundry.org
Sent: Wed, January 12, 2011 8:09:53 PM
Subject: Re: [Pgpool-general] replication/failover feature in Master/Slave mode

Hi,

Le 12/01/2011 15:10, Sandeep Thakkar a écrit :
> [...]
> I have a primary and a standby server on different boxes and both are running on 
> different ports. I would like to use pgpool for Streaming Replication and 
> Failover. Hence, I selected Master/Slave mode with stream. Now, I have a 
> question, if I write anything on primary, how will the data be replicated on 
> standby? Will it happen automatically like it does in replication mode Or do I 
> need to look into Hot Standby feature of PG?
> 

You need to look at the streaming replication feature of PostgreSQL. You
need Hot Standby for example if you want to use the load balacing
feature of pgPool.

> Also, on failover (let's say primary goes down for some reason), and the standby 
> now takes over. Will the standby has write operations?
> 

You need to write scripts for that.

> Also, in my application, will I use the pgpool port, so that I do not need to 
> change the configuration file in case of failover?? With Slony, we had to tell 
> the application to use the other port.
> 

The pgpool port, always.


-- 
Guillaume
http://www.postgresql.fr
http://dalibo.com

 

 

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