Re: How do you manage cluster replication and failover ?

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(at)maltem(dot)com]
Enviado el: viernes, 7 de abril de 2017 11:34 a. m.
Para: Lazaro Garcia; pgsql-admin(at)postgresql(dot)org
Asunto: RE: [ADMIN] 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.

_____

De : Lazaro Garcia < <mailto:lazaro3487(at)gmail(dot)com> lazaro3487(at)gmail(dot)com>
Envoyé : vendredi 7 avril 2017 15:26:41
À : Robin LUCBERNET; <mailto:pgsql-admin(at)postgresql(dot)org>
pgsql-admin(at)postgresql(dot)org
Objet : RE: [ADMIN] 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(at)postgresql(dot)org
<mailto:pgsql-admin-owner(at)postgresql(dot)org>
[mailto:pgsql-admin-owner(at)postgresql(dot)org] En nombre de Robin LUCBERNET
Enviado el: jueves, 6 de abril de 2017 05:18 a. m.
Para: pgsql-admin(at)postgresql(dot)org <mailto:pgsql-admin(at)postgresql(dot)org>
Asunto: [ADMIN] 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