You must delete missing volumes from Storage Foundation. This will make the drive letter or mount point available and will remove information about the missing volume that is no longer relevant.
For example delete the DB1 volume. Do not delete the DB1-tlogs volume.
To delete a missing volume using the VEA console
To delete a missing volume using the command line
vxassist -gExch-DG1 delete DB1
For the complete syntax of the vxassist delete command, see Storage Foundation Administrator's Guide.