To help minimization of packet loss, the operating system socket buffers need to be large enough to handle the incoming network traffic while your Java application is paused during garbage collection. By default Coherence will attempt to allocate a socket buffer of 2MB. If your operating system is not configured to allow for large buffers Coherence will use smaller buffers. Most versions of UNIX have a very low default buffer limit, which should be increased to at least 2MB.