I hope this is the appropriate place to post this question, it may be a geoserver issue but I'm at a loss.
I have been running Tomcat 6.0.29 as a service on Window Server 2003 for a couple of months with great performance. I'm using it to serve out 2 instances of Geoserver, using isapi redirect filter on IIS. This week I needed to add another instance of Geoserver, but found performance very bad with three instance running (many OOM errors despite 1GB max allocation), so decided to install a second Tomcat. This instance is up and running, also as a service, but I'm finding now when I access web pages that hit any of my Geoservers, about half of the map tiles (png images) are returning a 404 error. The rest of the tiles load just fine. No errors are being produced in the Tomcat or Geoserver logs. Does anyone know what might cause the 404 errors? Could it be a timout issue?