Our domain consists of 2 Windows 2008 domain controllers, along with a number of member servers.
It has been noticed that when either DC is pinged the response time varies between <1ms and often > 100 ms (average ~ 50ms). This is consistent pinging back from the DC to the original host.
To minimize the network tests were performed between servers ( ie DC + member server) connected to the same 1Gb switch.
Other things to note;
- Performing a ping on either DC to itself indicates <1ms consistently
- DC performance has been checked throughout pinging - no problems observed
- the DC firewall has been switched off (no change)
- one of the DC's is virtualized - other VM's do not exhibit the same random response times.
The random response times only appear when the ping traverses the network, leading to questions about NIC config etc. However, as this ONLY appears to affect the DC's, and one of those (VM) shares NIC's with other VM's that do not have this problem it seems that the NIC may not be the root cause.
Has anyone witnessed this phenomenon or know of any tests/fixes?