Обсуждение: Promoting 1 of 2 slaves

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Promoting 1 of 2 slaves

От
Joseph Kregloh
Дата:
Hello,

I am getting ready to take my master server out of service today and promote the slave to take it's place. In my current setup I have one master server which ships WAL files to two separate slave servers.

My plan is to promote one of those slaves. How do I get the slave that I promoted to start replicating to the other slave the moment I trigger it's promotion?

Thanks,
-Joseph Kregloh

Re: Promoting 1 of 2 slaves

От
William Dunn
Дата:
As I am aware, you would have two options depending on your configuration:
  1. Change the primary_conninfo value on the second standby's recovery.conf to point to the standby that has been promoted to master. However, I think this would require that instance to be rebooted for the configuration changes to take effect
  2. Modify the DNS entries so that the host value in primary_conninfo points to the new master rather than the old master
Does anyone know of another way?

Will J. Dunn

On Fri, Jul 17, 2015 at 9:43 AM, Joseph Kregloh <jkregloh@sproutloud.com> wrote:
Hello,

I am getting ready to take my master server out of service today and promote the slave to take it's place. In my current setup I have one master server which ships WAL files to two separate slave servers.

My plan is to promote one of those slaves. How do I get the slave that I promoted to start replicating to the other slave the moment I trigger it's promotion?

Thanks,
-Joseph Kregloh

Re: Promoting 1 of 2 slaves

От
Joseph Kregloh
Дата:
What I ended up doing was:

1. Stopping the master.
2. Triggering the promotion of slave A.
3. After slave A was promoted I turned it off and modified the postgresql.conf file to make it a permanent master and setup WAL shipping to slave B.
4. Rsync the pg_xlog directory from slave A to slave B and set recovery_target_timeline to latest
5. Start slave B, then start slave A now master.

So far everything seems to work.

-Joseph Kregloh

On Tue, Jul 21, 2015 at 2:37 PM, William Dunn <dunnwjr@gmail.com> wrote:
As I am aware, you would have two options depending on your configuration:
  1. Change the primary_conninfo value on the second standby's recovery.conf to point to the standby that has been promoted to master. However, I think this would require that instance to be rebooted for the configuration changes to take effect
  2. Modify the DNS entries so that the host value in primary_conninfo points to the new master rather than the old master
Does anyone know of another way?

Will J. Dunn

On Fri, Jul 17, 2015 at 9:43 AM, Joseph Kregloh <jkregloh@sproutloud.com> wrote:
Hello,

I am getting ready to take my master server out of service today and promote the slave to take it's place. In my current setup I have one master server which ships WAL files to two separate slave servers.

My plan is to promote one of those slaves. How do I get the slave that I promoted to start replicating to the other slave the moment I trigger it's promotion?

Thanks,
-Joseph Kregloh