We are having some strange behaviour and hoping to find some clues...
we have 3 VCenter servers, with several ESXi 4.1 and ESX 4.0 servers. We see random disconnects on VCenter. The hosts disconnect, and then reconnect (by themselves) within a few seconds. Some times its 4 to 5 seconds, some times the disconnects last for a 10 seconds. The host would just reconnect and we do not have to do anything.
All Vcenter servers are windows 2008 64bit, In 2 instances of Venter, the Database is local and the on the third instance, the databse is on another server. But, we see Host disconnects on all 3 ESX servers. We have more than 50 hosts per vcenter, and its not isolated to ESX hosts. On one VCenter server, the firewall is enabled with a rule to allow all ports. On another Vcenter server, the firewall is disabled.
I have ping running from the vcenter servers while the host disconnect and do not see a single packet drop. We use DNS and all DNS entries look good.
We have HA configured and worring if the disconnect last for more than 14secs, the host may go into isolation mode....
Any help is greatly appreciated.
you may want to start at the KB article below
Also, ensure all your vCenter instances don't have the wrong IP address listed for Managed IP Address. This can be found by going to Administration--vCenter Server Settings--Runtime Settings--Managed IP address.