There are errors on Events tab:
Ha agent on XXXESX1 in cluster XXX in cluster XXX in datacenterXXX has an error.
After that there is messages of:
Insufficient resources to satisfy HA failover on cluster XXX in datacenterXXX
Ha agent on XXXESX2 in cluster XXX in cluster XXX in datacenterXXX has an error.
Unable to contact a primary HA agent in cluster XXX in datacenterXXX
-after this the virtual machines are disconnected (they keep running though)
ssh console connection to esx gives an error:
resource temporary unavailable
It also seems that this happens on some sort of regular intervals.
Atleast the times when the first ESX has reported the error seems to be roughly the same (at 4:50 am).
There are roughly 4-5 days between, before the error reoccurs.
Currently the only fix we had, is to reboot both ESX servers.
We have a setup of 1 virtual center (ver 2.5) and 2 ESX servers (ver 3.5).
We have only few virtual machines currently running.
Im happy to provide any additional information.
Thanks for all your help.