You want to unmount a datastore in VMware ESXi but can’t because you get an error: ‘Cannot unmount volume ‘Datastore Name: Datastore1 uuid: 5204515c-e09a154d-9e1b-001a14c85540′ because file system is busy. Correct the problem and retry the operation.’
You may also receive the error ‘The resource is in use; Call “HostDatastoreSystem.RemoveDatastore” for object datastoresystem on ESXi failed’
First of all try and see if the datastore is seen as being in use by ESXi. Within VSphere select the Maps tab and look at the diagram. You should be able to see straight away if the datastore is being used by a virtual machine.
Then if you are still having trouble go to Hosts and Clusters and go to the Manage Tab. Go down to Advanced System Settings and then go to Syslog.global.logdir. You will see that the currently configured log location is [<yourdatastoresname>] Logs. We will need to change this to a local path in order to unmount the datastore. If you do not change the path the store cannot be unmounted as the path is constantly being written to.
Once you have changed the path try and unmount the store again, it should work.