If I am not mistaken, the requirement is for at least approx. 603MB of free disk space available.
The actual requirement should be printed as an info message to the installation.log file like:
"Space needed: xxxx kB"
as Andrew said, the space requirement is written to installer log file, which is installation_<PID>.log. It should also appear in the error message printed to the console when installer detects insufficient disk space available.
Furthermore, please note that this size is only a minimum required for the installation to succeed, additional space is needed for runtime data generated by the agents (logs, application crash reports, etc.).