Websphere Max memory allocation for JVM

When you set the max memory size on websphere  7 installed on 32 bit machine – you will get the next warning:

 You have set the Maximum heap size field to a value greater than 2 gigabytes. This is only valid on a 64 bit server. You can ignore this warning if the server will run in 64 bit mode; otherwise, the maximum value is 2048.

The server failed to startup on 32 bit machine when I set  the max memory to 2200 (M).
in the startServer.log - you can find such logging:

ADMU7704E: Failed while trying to start the Windows Service associated with server: server1;
probable error executing WASService.exe: Starting Service: YANIVTNode01
Service failed to start.  startServer return code = -1



I test it on 64bit server , I set the max memory to 2500 , and the server startup successfully.
Summary:
If we want more than 2G RAM allocation for websphere on windows  , you must used 64Bit server.

enjoy 

Yaniv Tzanany