Xcentrisity BIS uses a system resource called a "Thread" to render pages. For efficiency, BIS maintains an internal pool of threads, and when a request for a BIS page arrives, a thread from the pool is dispatched to serve the page.  If there are no available threads in the pool, the request must wait for a thread to become available. A request will wait for some period of time (normally about 60 seconds) before being denied with a “server too busy” error page.

The BIS_MAX_THREADS environment variable may be used to increase (or decrease) the size of the thread pool. The syntax is:

BIS_MAX_THREADS=n

Where, n, is an integer value that specifies the number of threads that will be used by BIS to service requests.  The default value for n is 5.