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Re: How much memory(RAM) required for OS running Oracle

From: joel garry <>
Date: Thu, 05 Jul 2007 13:37:41 -0700
Message-ID: <>

On Jul 5, 7:42 am, wrote:
> Hi,
> We are setting up couple of boxes on Linux with different hardware
> specs and trying to prepare a document that can be used as general
> guidelines for future installations.
> In SQL Server installations, for system with <16GB we allocate 1GB for
> OS and rest of memory for Database and for system with >16GB we
> allocate 2GB for OS and rest of memory for database.
> So we are wondering how much memory is required by OS(Linux) for
> Oracle installation and allocate remaining memory for Database (SGA +
> PGA etc).
> Also By default Oracle recommends 40% of RAM for SGA but that may be
> good for small system but may not be applicable for large system. It
> is also true that we can't have a generic set
> of recommendations since it also depends upon the application and
> other factors etc but still it will be good to have some starting
> point (not 40%) so that DBA can configure the system and then modify
> the settings as required. It may be possible that such type of
> document already exists and it will be great if can point me to
> location or send me your feedback about what can SGA+PGA are set for
> particular RAM on machine, so document will look like:
> 2
> 4
> 8
> 12
> 16
> 32
> 64
> Environment: Oracle on RHAT4
> Thanks
> --Harvinder

You can't really be that generic because of the wide variation of applications, options and configurations. If you know ahead of time a limited number of applications and configurations, maybe you can empirically determine these things for your organization. But if you are going to have a data warehouse, a third-party app, XE and custom shared-server in your organization, for example, each will have widely varying requirements based not least on number of users.

Metalink has some docs on how to figure out unix memory usage and such, poke around there. There are a few how-to-configure methodologies floating around (IIRC a google for Shallahammer might find something), but really, you need a DBA to empirically test for details once you have something up and running. The more recent versions of Oracle can work with the defaults at least to get started, some DBA's might have rules of thumb for buffers and optimization parameters for particular types of workloads. Most large applications like ERP or MRP have some recommendations.

I think some docs about PGA settings may be misleading (or at least only applicable to narrow configurations that are not specified clearly).


-- is bogus.
"New size for Men especially for new feelings of women at once!" -
Received on Thu Jul 05 2007 - 15:37:41 CDT

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