For our setup here, we have 2 load-balanced Windows 2003 Servers with PHP using FastCGI & IIS6 that host a multitude of websites -- probably 30 websites or so. The largest website gets about 5000 hits / day (<100 concurrent users) and most of the others get 500 or so hits a day, max.
Each website is in its own Application Pool, for the record.
Essentially, what ends up happening is, with no spike in traffic, one of the servers will go down. The CPU ends up reaching 100%. We don't know why. One thing we have noticed, though, is that in the Task Manager, when the CPU is at 100%, it's as if there is an inordinate number of php-cgi.exe processes running at once -- as if the processes are not closing. There are many occasions we will have much fewer processes and higher numbers of people on the site.
We're trying to figure out if this is a setting that we could've missed on the PHP / IIS6 installation and settings, or if it's something else altogether that we're not looking at. I've scoured the web for people who perhaps had the same problem but have been out of luck regarding solutions. I've checked our ini and conf files to see if I could find anything out of place, but no such luck.
Has anyone seen this before? Perhaps we're looking at the wrong things altogther?
Thanks in advance, stackOverflow geniuses!
When server went down:
And on a normal occasion: