[pgpool-general: 1415] Re: Hosting several pgpool-II on the same server

[Tatsuo Ishii]

> Hi,
> 
> I am a PostgreSQL DBA and am working on pgpool-II 3.2.1/3.2.2 since a few weeks.
> 
> At work we decided to integrate pgpool-II 3.2 to our PostgreSQL system. We are using PostgreSQL 9.1 with streaming replication (3 slaves with "Asynchronous" replication mode).
> 
> On production there is only 1 replication system (streaming replication: 1 master + 3 slaves)
> 
> For our customers we plan to duplicate this system (the same replication system: 1 master and N slaves). It implies to have 
> 
> My question are
> 
> -  Is it doable to host all pgpool-II services on the same server (one different port per PostgreSQL cluster)? (1 pgpool service for each replication system)

Yes. You should assign different port etc. to each pgpool-II. Zapping
pgpool.conf.sample shows that at least following directives need to
have different value:

port
pcp_port
pid_file_name
logdir
memqcache_oiddir

Plus probably you want to have dedicated directory to locate
pgpool.conf under it, because the diectory pool_passwd resides in is
implicitly assumed to be the same directory where pgpool.conf lives.

> - If we go this way (hosting all pgpool-II on the same server) then is there any tuning to do or any recommendation/suggestion (RAM, CPUs....)?

You need to give enough RAM to each pgpool-II until it is not suffered
by excessive paging. More than that would be probably waste of
resource(you cannot expect better performance even if you give
pgpool-II too much memory). Regarding CPUs, I recommend as many as
CPUs as possible. If you have lots of concurrent active sessions, each
session needs CPU resource.

> Thanks for your cooperation.
> 
> 
> Jean David TECHER.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
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