Message-ID: <4B87E066.7080702@uci.cu>
Date: Fri, 26 Feb 2010 09:53:26 -0500
From: "Ing. Marcos Ortiz Valmaseda" <mlortiz@uci.cu>
User-Agent: Thunderbird 2.0.0.23 (X11/20090817)
MIME-Version: 1.0
To: elias ghanem <e.ghanem@acteos.com>
CC: pgsql-performance@postgresql.org
Subject: Re: Multiple data base on same server
References: <201002260934.o1Q9Xxka014571@relay-ext.ornis.com>
In-Reply-To: <201002260934.o1Q9Xxka014571@relay-ext.ornis.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 8bit

elias ghanem escribió:
>
> Hi,
>
> I’m using postgresql 8.4
>
> I need to install multiple postgresql dbs on one server but I have 
> some questions:
>
> -Is there any problems (performance wise or other) if I have 10 to 15 
> DBs on the same server?
>
> -Each DB needs 10 tablespaces, so if I create 10 different tablespaces 
> for each DB I will have 100 to 150 table space on the same server. So 
> can this also cause any problems?
>
> Thanks
>
It´s depends of the features of the server. If is a good server, for 
example of 16 GB to 32 of RAM, with 8 a 16 processors, with a good SAN 
with RAID -1 for the pg_xlog directory and RAID-10 for the $PG_DATA 
using ZFS if you are using Solaris or FreeBSD and xfs or ext3 using 
Linux , on a Operating Systems of 64 bits, I think that this load can be 
supported.

There are installations of PostgreSQL with more than 400 db, but the 
environment is very distribuided on several servers.
About the tablespaces, It´s very necesary to have 10 tablespaces on each 
database? Normally, you can separate the table or the tables with more 
activity to a rapid disc array (I ´m thinking on a SSD array), other 
tablespace for the indexes if you have many, and for example with 
pl/proxy you could handle the partitions of your data.
There is not necessaty to have 100 or 150 tablespaces on the same 
server. You can separate this on a SAN, you can have two or more main 
PostgreSQL servers and several slaves with the data replicated on any 
case of data corruption on the main servers.
Rebember look the configuration of the performance of the PostgreSQL 
servers: work_mem, shared_buffers, etc
Regards and I hope that comments helps to you.