I have recently started at an organisation which has a fairly new virtualised installation. I have taken over from someone else who is in the process of moving to another department in the organisation, so knowledge can be obtained as to the history of the system.
I have a system which consists of two clusters - one Production and one Disaster Recovery. Each cluster is based on it's own set of system hardware - seperate Blade Centre's, SAN's etc etc. I can provide more information on this, if it helps to resolve the issue. :)
My issue is this...
We had a requirement to shutdown the Disaster Recovery hardware over the weekend due to some power work that was occuring. As the system as a whole is in a state where it is running on Production, I thought that we would be able to take the DR system down without much of a hiccup. Okay, the system wouldnt be visable in the Client and vCentre might complain about not being able to communicate. We also run DoubleTake, so thought that it might also complain about not being able to replicate. But generally we expected the system to run without much of an issue.
However, this was not the case. Shortly after shutting down DR, we started getting calls about machines being unable to connect to the system. Rebooting seemed to fix this, so we thought all was well. About an hour or so later, more machines were experiencing issues and even our own machines couldnt connect. We decided to reboot the network switches but to no avail. We then bought the network switches back online in the DR system, thinking that if there was a network config issue in the switches, this would resolve the issue. But no. The last thing to do was bring the BladeCentre back online and boot up the servers. Once everything was back up and running again (after a few minutes) the issue resolved itself.
This therefore would suggest that there is some sort of issue with the vSphere Cluster being down that caused our network outage problems, but we're puzzled as to how. If someone is able to shed any light, I would be most appreciative.