I recently removed a physical host from a vCenter Server virtual appliance and am not able to add it back to vCenter Server because I get an error about the datastore already existing. I am running a simple vCenter Server environment with two physical hosts and shared storage. I have only been administering vCenter for a few months, so I am relatively new to the technology and processes. I have searched the Internet for a few days now, but have not found any documentation of anyone experiencing the same problem as I (which I find odd considering how simple my configuration and problem), so I wanted to get some help from the VMware community.
I got an error message one day that vCenter Server couldn't connect to one of the two hosts so I removed the host (instead of disconnecting and connecting as I should have done). Now I am not able to connect the host to vCenter server because the shared storage datastore conflicts with the same datastore used by the existing host in vCenter Server. The error message I get is ""Datastore 'datastore_name' conflicts with an existing datastore in the datacenter that has the same URL (ds:///vmfs/volumes/UUID/), but is backed by different physical storage." I try to unmount the datastore from the host, but get the following error message: "The resource 'Datastore Name: datastore_name VMFS uuid: UUID' is in use." The error stack says, "Call "HostStorageSystem.UnmountVmfsVolume" for object "storageSystem" on ESXi "IP address" failed. Cannot unmount volume 'Datastore Name: datastore_name VMFS uuid: 'UUID' because file system is busy. Correct the problem and retry the operation." I have tried removing all virtual machines from inventory, putting the hosts in maintenance mode, rebooting the physical hosts, but none of my troubleshooting is helping.
I am not sure what steps to take to get this datastore unassociated with the host so that I can add it back into vCenter Server. Any help you can provide me is appreciated.
