On 6.3.0 SP3 if network utilization/CPU usage is high (and at high priority) network connection between nodes might be 
lost for a while. In that case unblock pulse sent by signal deliveted to a thread blocked in read() might be lost (not 
delivered to server) while connection recovers to alive state after short time and file remains open/read remains 
pending. That causes deadlock in client application since it expects read() to exit with EINTR but it never would.