I believe that I saw something unusual here.
I have a 3 node cluster (with GFS) using CMAN. After I shutdown 2 nodes in short time span, the cluster shows it lost quorum, but I run the clustat on the third node, and clustat shows the cluster has 3 nodes (2 are offline) and the other services are up. I was able to access/read the share storage. CMAN_TOOL shows cluster lost quorum and the activity is blocked. What I expected is that I should not allow accessing the shared storage and other services at all when the cluster lost the quorum. Anyone has seen the similar things? What/where should I look into?