On 29/03/11 11:29, mcclnx mcc wrote: > To answer your questios: > > 1. network is Intranet not internet. > > 2. servers CPU and I/O are very light. We did use "sar -u" and sar -b to check. > > 3. is NOT only one server has this network slow problem. at least 4 to 5 servers on that rack all report slow. it is NOT possible all servers on that rack are all heavy load. > Try using 'nethogs' during the time when network is slow on the suspect machines. It will show you which processes on the local machine are hogging the network bandwidth! I don't know why I explained that last part; it is self explanatory :) I was most likely talking out loud, so forgive me! Ak.