Re: How do you manage cluster replication and failover ?

["Lazaro Garcia" <lazaro3487@xxxxxxxxx>]

You can user pgbouncer  + repmgr but pgbouncer is not a load balancer.

 

When repmgr performs failover you can configure the property promote_command in repmgr.conf and build an script for updating the pgbouncer configuration with the new master.

 

Repmgr + pgpool would be very usefull when you have more than 2 nodes because pgpool does not knows how is the best candidate node for promoting to master.

 

Regards.

 

De: Robin LUCBERNET [mailto:rlucbernet@xxxxxxxxxx]
Enviado el: viernes, 7 de abril de 2017 11:34 a. m.
Para: Lazaro Garcia; pgsql-admin@xxxxxxxxxxxxxx
Asunto: RE: How do you manage cluster replication and failover ?

 

Hey, thanks for your feedbacks.

 

I do not know about Patroni. I will have a look at it.

 

Could someone confirm me that all features of pgpool (connection pooling + automatic failover) can be achieve using pgbouncer (connection pooling) + repmgr (automatic failover) ? Is it not overkill to user repmgr + pgpool ? Am I missing something ?

 

Robin.

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De : Lazaro Garcia <lazaro3487@xxxxxxxxx>
Envoyé : vendredi 7 avril 2017 15:26:41
À : Robin LUCBERNET; pgsql-admin@xxxxxxxxxxxxxx
Objet : RE: How do you manage cluster replication and failover ?

 

You can use repmgr because it performs automatic failover, promotes a master mores closer to replica and follows other slaves to new master.

 

 

Then pgpool detects the new master promoted by repmgr.

 

Regards.

 

De: pgsql-admin-owner@xxxxxxxxxxxxxx [mailto:pgsql-admin-owner@xxxxxxxxxxxxxx] En nombre de Robin LUCBERNET
Enviado el: jueves, 6 de abril de 2017 05:18 a. m.
Para: pgsql-admin@xxxxxxxxxxxxxx
Asunto: How do you manage cluster replication and failover ?

 

Hello,

 

We are currently trying to setup a multi hosts databases cluster with goals:
 * replication (no data-loss is "required", replication timing do not needs to be instant)
 * failover
 * load-balancing (bonus)

 

We tried:
 * synchronious replication (pgpool replication mode) + load-balancing (pgpool) : very interesing as we can theorically failover on any node at any moment. But even after several configuraation tweeks, we never succeed getting good write performance.
 * asynchronious replication (postgres 9.6 streaming replication) : good write performance, good replication timings (< 1 second for small transactions). We could loadbalance select requests using pgpool.

 

How do you manage your postgresql clusters ? Do you use pgpool ? pgbouncer ? other ?
How do you manage to single access point ? usign pgpool ? pgbouncer ?
Do you use streaming replication ? WAL archiving ? How do you handle to automatic failover ?

 

Robin