Symptoms
There is yellow exclamation mark on MARVIN-Virtual-SAN cluster, the reported alarm is virtual SAN health alarm 'Limits - After one additional host failure'.
The alarm details, "Checks the Virtual SAN components limits, disk space and RC reservations assuming one host failure."
Refer the Image below:
Cause
In addition to the basic limit health check, there is also a simulation of how resources would look like after an ESXi host failure has occurred.
Resolution
Please refer the VMware KB: https://kb.vmware.com/kb/2108743 which provides detailed information about Limits Health alarm.