Some changes have been made over the past couple of weeks that have made additional use of WinCache that has resulted in significant improvements to the site's response time. But now, it seems that PHP with FastCGI is becoming a bit unstable and we are seeing intermittent 503 Server overloaded errors.
We are running this on Server 2k3 - IIS6
The fastcgiext.ini reads as follows
EnvironmentVars=PHP_FCGI_MAX_REQUESTS:10000
ActivityTimeout=700
IdleTimeout=120
RequestTimeout=900
InstanceMaxRequests=10000
MaxInstances=0
SignalBeforeTerminateSeconds=10
StderrMode=IgnoreAndReturn200
Prior to the improvements - this setup was stable for a considerable time - now not sure where to begin in determining the problems with the 503 server overloaded messages.