Server Utilization Spikes

[Ayman Altounji]

We are using Novell 5.0 with 68 workstations attached through a 10/100 baseT hybrid network (12 stations are still 10BaseT). Periodically during the day, with no discernible workload changes, the resource utilization on the monitor screen will spike from a typical 1-4%, to 40-50% and higher. It remains at this level for 3-5 minutes, then resumes normal processing. During this spike, the console becomes unresponsive and all worstations on the server literally "freeze". Please advise if there are any diagnostics we can utilize to determine why and how to correct this problem. Thanks.