by Steve Kleine.
I have been fighting the same issue on Windows 2008 R2 for months without success, but IIS internals are a weak area on knowledge for me.
So far I've:
- changed the Application Pool account to localSystem
- Modified timeout for FastCGI (as you have)
- Set up a scheduled Moodle application pool recycle every four hours (seemed to give more stability but not completely)
- Got the cron job to run every two hours (seems to exacerbate the issue)
- Turned on failed request tracing for FastCGI (all it shows is the timeout and no root cause preceding it)
- Changed max_allowed_packet = 8M and max_connections in MySQL from 100 to 1024
- Turned off buffering per http://stackoverflow.com/questions/7178514/php-flush-stopped-flushing-in-iis7-5
The good side effects have been minimal.
Our install was from Microsofts's Web Application installed and we're running Moodle v2.3.2