While recommending for Hardware Sizing, ensure that the Database servers the ct is going to procure is a 64-Bit processor (depending up on the number of users).
In 32-Bit processor the sga_max_size cannot be increased more than 1.78 Gb (even when /3g switch is enabled). This restriction leads to re-sizing of the hardware and could leads to loss in business.
In a 64-bit processor the above said incompatibility was overridden
How to check the ORACLE installed is 32-Bit or 64 Bit ?
cd $ORACLE_HOME/bin
file oracl*
This will display the file type of your oracle binaries. If you are running 64-bit binaries, the output should look like this:
oracle: ELF 64-bit MSB executable SPARCV9 Version 1, dynamically linked, not stripped
oracleO: ELF 64-bit MSB executable SPARCV9 Version 1, dynamically linked, not stripped
If your binaries are 32-bit, the output will look like this:
oracle: ELF 32-bit MSB executable SPARC Version 1, dynamically linked, not stripped
