As Delphix presents all database mounts over NFS for provisioning virtual database (VDB), these mounts would be stale if Engine Reboots...
In this situation, VDB instance might be running until database timeout kicks-in (typically 15 minutes), but all the read-write operations would be queued up and it would not be usable. The VDB status in Delphix finally would show with “Inactive” status...
To resolve this situation, VDB needs to be re-started using either the graphical user-interface (GUI) or command-line interface (CLI) option. In some situations, those stale NFS mounts would not get cleaned up on Target server and trying to start VDB would throw following error:
In that situation, first try to enable/disable VDB and then check if the stale NFS mounts are cleared, otherwise work with your UNIX/Linux SysAdmin team to clear those mount points and afterwards re-try starting the VDB using Delphix.
Note: VDB cannot be started from Target server directly as database mounts are unavailable in the condition described.