I have a little problem with Apache Servicemix and the thread pool. Indeed when the number of threads exceeded 4000, my Servicemix crashes.
I saw here http://servicemix.apache.org/thread-pools.html some informations, but nothing to vary the max number of threads...
Could you elaborate what you mean by "my Servicemix crashes"?
Generally maximumPoolSize can give large thread pool, but more thread means need more memory, so it also depend on your process memory, so you may need allocate more memory for servicemix.
Try using -Xmx1024m to allocate more memory to see if it helps.