I recently ran into an issue where I was could not unmount an empty vSphere datastore from the appropriate hosts. After doing some research I found out that this issue was caused by open files from a new VSAN-related service known as “vsantraced”. According to this VMware KB article, you must perform the following steps in order to unmount the affected datastore(s):
- Login to the vSphere host via SSH
- Stop the “vsantraced” service
/etc/init.d/vsantraced stop
- Unmount the datastore(s)
- Start the “vsantraced” service
/etc/init.d/vsantraced start
For more details please see the VMware KB article linked to above.