Re: Thoughts on Linux, Oracle, and VLM

From: Jared Still <>
Date: Sat, 21 Apr 2012 09:52:14 -0700
Message-ID: <>

On Tue, Apr 17, 2012 at 9:11 AM, Andrew Kerber <>wrote:
> .... So on VLM systems, it is entirely possible the
> required OS memory number may be some fixed amount as opposed to 20% of the
> total system memory. eg, on 256G RAM system, its very possible that Linux
> needs a flat 25G instead of the 50G or so that my 80% rule of thumb
> suggests. Do any Linux experts have input?

I don't claim to be a linux expert, but nonetheless have some thoughts on the matter.

The amount of memory required by the server will vary with the number of connections
to the database(s). With 1+ databases on a server, there could be quite a large number
of connections.

At the moment I can't recall an approximate amount of memory that an 11g dedicated
server process might consume, but a couple thousand of them would eat up a fair
bit of memory.

And while applications with server pools often (frequently? usually? ) make far too many
connections to the database, there's often little or nothing the DBA can do to change that,
so we have to just deal with allocating the memory as best we can.

This 1 factor makes it difficult to assume a rule of thumb. There are probably others
to consider as well, but this is what immediately came to mind.

Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist Oracle Blog: Home Page:

Received on Sat Apr 21 2012 - 11:52:14 CDT

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