Install Oracle Clusterware/RAC Windows x32bit or Windows 64bit ?

Question

Hi,
What is your suggestion to install Oracle Clusterware RAC on Windows.
Why choose Windows 32 bit ?
Why choose Windows 64 bit?
What are the advantages and disadvantages?

Answer 1

Hi,
I definitely recommend 64bit Windows, the principal reason is memory addressing limitation.
In my standpoint do not exist benefits to use Windows 32bit with Oracle Clusterware/RAC.
32-bit processors have address registers that are 32-bits wide (can address up to 4GB physical RAM).
You can to use a workaround by enabling the addressing of more than 4GBytes using parameters in Windows (AWE/PAE). But if I want to use more than 4Gbytes, I'll go to Windows 64bit.
The 4GB addressable space per process is divided into system and user space. By default, the system space is 2GB and the private user space is 2GB. Each user process shares the same 2GB System address space.
The services of the Clusterware, ASM and Listener will consume at least 1Gbyte of memory initially.
If you create an instance to to use 1Gbytes and you have 50 connections you will have problems with connections to the database raising the following error.
  TNS-00510: Internal limit restriction exceeded
    32-bit Windows Error: 8: Exec format error
TNS-00507: Connection closed
    32-bit Windows Error: 109: Unknown errorReason: Problems of memory usage. i.e. Out of Memory.
Another point:
With Windows 32-bit using Clusterware/RAC 11.1 you can set Automatic Memory Management(AMM) feature (MEMORY_TARGET) but you cannot use if you create 2 Instances on same Host.
Check this note..
*ORA-27102, OSD-00031 Unable To Extend Memory_max_target And Memory_target Past 2GB [ID 842881.1]*
Oracle Solution: Please install the 64-bit OS on 64-bit server, hence there is no memory limitations
I belive that is reason wich Oracle not support Oracle Grid Infrastructure 11.2 on Windows 32-bit. You cannot use ASM 11.2 on Windows 32-bit.
Definitely do not exist reason for me to to use Windows 32bit to support Oracle Clusterware.
There are lot services involved  wich require memory and a big limitation of memory on 32-bit.
At present all latest CPUs support 64bit. Then install Oracle Clusterware/RAC x64, even when you are use less than 4GBytes memory, you only have benefits.
Benefits of Use 64-bit are:
64-bit versions of Windows have implemented up to 16 terabytes of virtual address space
64-bit programs use the 16 terabyte tuning model (8TB user / 8TB kernel)
No performance penalties for large memory
Unlimited user connectivity
64-bit Windows versions allow addressing of large physical memory sizes without using PAE
*Windows Memory Configuration: 32-bit and 64-bit [ID 873752.1]*
This document gives a better understanding of my perspective.
http://levipereira.wordpress.com/2011/02/12/comparison-of-32-bit-and-64-bit-oracle-database-performance-on-the-dell-poweredge-6850-server-with-microsoft-windows-server-2003/
Regards,
Levi Pereira