In Tomcat's acceptCount attribute is described as
The maximum length of the operating system provided queue for incoming connection requests when maxConnections has been reached. The operating system may ignore this setting and use a different size for the queue. When this queue is full, the operating system may actively refuse additional connections or those connections may time out. The default value is 100.
Does incoming connection requests consume file descriptor in OS? If so, what's the difference between increasing maxConnections and increasing acceptCount?
I think that it is always good to set acceptCount=1 and set maxConnection as high as possible, because it reduces overheads from using operating system's queue.