One of our vSphere host showed as disconnected in vCenter. Connecting directly to the host with the vSphere client wouldn’t work neither. When restaring the services on the host I was able to connect directly but within one minute the connection between the client and the host would be lost.
As I had already encountered something similar before I checked the partitions on the hosts.
The vdf -h command shows that the hostdstats partitiion has filled up. This was new to me. On previous similar issues it was the MAINSYS partition who ran out of space. Check this KB article to solve the MAINSYS filling up issue.
The content of this partition is located under /var/lib/vmware/hostd/stats. Here we see that the hostAgentStats-20.stats file is the cullprit.
Delete the hostAgentStats-*.stats file from /var/lib/vmware/hostd/stats. Run services.sh restart on the vSphere host.
Problem should be solved now.