Re: Oracle memory allocation on Linux 2.6

From: NetComrade <>
Date: Wed, 02 Apr 2008 16:16:34 GMT
Message-ID: <>

On 01 Apr 2008 16:28:26 GMT, Mladen Gogala <> wrote:

>On Tue, 01 Apr 2008 07:37:48 -0700, vitalisman wrote:
>> With the latest Linux kernels, things have gotten hard to tune regarding
>> the SGA/PGA we can allocate. I'm mainly talking about the physical
>> memory that is allocated to the OS buffers/caches to make full use of
>> the memory. With earlier kernels, we had vm.pagecache to control easily
>> these amounts of memory. Now there is vm.swapiness with the unfathomable
>> algorithm behind it (read: AFAIK we cannot really control the OS
>> buffers/caches anymore.)
>True. Linux is beginning to imitate Windows, even the shortcomings.
>No control over the VM that Unix OS was renowned for. Linux, too, started
>with undocumented algorithms and is taking control away from the system
>administrators. It is beginning to resemble an ego trip of yet another
>"IT industry giant", namely Ken Olsen. To make long story short - Linux
>sucks. I am awaiting a competing OS. What they did with 2.6 is a disaster.
>Competitor is bound to appear, sooner or later. My money is on some flavor
>of BSD. This is not the first time things like that have been discussed
>here. As far as I can recollect, Noons was also very critical of Linux,
>same as Kevin Closson.
>> Moreover, SGA locking is not possible (or rather not advised by Oracle
>> support) and it is really difficult to check how much physical memory
>> our SGA is actually using. Even with vm.swapiness=0, huge amounts of OS
>> buffers/caches get
>Do you have FILSYSTEMIO_OPTIONS set to either "SETALL" or "DIRECTIO"?
>In my experience, that will significantly reduce the use of caches.

Have you tried playing with Veritas/ODM?

We run Oracle 9iR2,10gR2, 10g2RAC on RH4/RH5 and Solaris 10 (Sparc) remove NSPAM to email Received on Wed Apr 02 2008 - 11:16:34 CDT

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