Re: Help: System requirements for postgresql 7.4.1 - Mailing list pgsql-admin

From Thierry Missimilly
Subject Re: Help: System requirements for postgresql 7.4.1
Date
Msg-id 401A10B7.D9307B90@BULL.NET
Whole thread Raw
In response to Help: System requirements for postgresql 7.4.1  ("Juan Carlos Diez" <jdiez@eluniversal.com>)
List pgsql-admin
Hi,

In fact it is difficult to answer to that questions as they depend of how big is your database, how many simultaneous
connectionsyou 
have, ... etc
But, I can help you by giving you my results on a Bi-CPU Xeon 2.6 GHz , 4 Gb RAM, external 2  x RAID0 on four disks
eachwith Redhat 
9.0.

1) Connections : This system support easily 500 simultaneous connections. The performances decrease only by 11 %
between100 users and 
500 users.

2) Database size : This is a bit more complex. If your database size is 700 Mb (less << RAM size) the performances are
verygood. But 
when the database size is bigger than the RAM size, the I/O increased rapidly and your system spend time in Wait I/O
state.For 
example, I have noted that from 700 Mb to 7 Gb the performances drop by 65% on my 4 GB memory machine. That' s don't
meansthey are 
bad but that means that if you want to improve performances on very big Database you should have to spend money to
increasethe I/O 
throughput instead of bought more CPUs.
Please note that this remarks is valid on other RDBMS, even on commercial RDBMS.
Please note too, that there is about 30 % of performance gain between SCSI internal disks and an external RAID0
ChaparralLUN. 

About the software, I have preferred to install my own downloaded Postgres 7.4 version as the Database Redhat package
isa less recent 
Postgres version (7.2 or 7.3) and a lot of things have been improved in the 7.4. Further more, I prefer to install all
Postgresbin 
and lib in /usr/local/pgsql than in /usr/bin and /usr/lib.

Thierry Missimilly

Juan Carlos Diez wrote:

> Hello, I'm evaluating that version and I can't find system requirements for it. Could anybody please help me with
thesequestions? 
>
> 1.1. Hardware:
> 1.1.1. C.P.U. (how many processors, what speed)
> 1.1.2. Ram. (minimum and desired)
> 1.1.3. Disk.
> 1.1.4. Networking.
> 1.1.5. Scalability
>
> 1.2. Software:
> 1.2.1. OS. (wich versions and patches are required for linux and solaris)
> 1.2.2. Required software packages.
>
> Thank you very much.
>
> Best regards,
>
> JCD.
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster

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