I had this question a number of times now. Those of you familiar with VSAN will know that if a component goes absent for a period of 60 minutes (default) then VSAN will begin rebuilding a new copy of the component elsewhere in the cluster (if resources allow it). The question then is, if the missing/absent/failed component recovers and becomes visible to VSAN once again, what happens? Will we throw away the component that was just created, or will we throw away the original component that recovered?
While doing some testing yesterday in our lab, we noticed that after we had placed a host participating in a VSAN cluster into maintenance mode and chose the option to evacuate the data from the host to the remaining nodes in the cluster, the “Enter Maintenance Mode” task was still sitting at 63% complete even though it seemed that the resynchronization of components was complete. For example, when we used the vsan.resync_dashboard RVC command, there were 0 bytes left to sync: > vsan.resync_dashboard /localhost/ie-datacenter-01/computers/ie-vsan-01/ 2014-11-06 12:07:45 +0000: Querying all VMs on VSAN … 2014-11-06 12:07:45 +0000: Querying all objects ..…