Volume efficiency operations do not complete and show the error "Metafile does not exist"

Applies to

Data ONTAP versions 8.3.2 and later.

Issue

Volume efficiency (deduplication) operations fail and give the error Metafile does not exist. This can be seen in the following output:

cluster01::> volume efficiency show -vserver svm1 -volume vol1
 
                 Vserver Name: svm1
                      Volume Name: vol1
                      Volume Path: /vol/vol1
                            State: Enabled
                           Status: Idle
 Progress: Idle for 01:20:04
                             Type: Snapvault
                         Schedule: -
           Efficiency Policy Name: -
           Blocks Skipped Sharing: 0
             Last Operation State: Failure
     Last Success Operation Begin: Fri Jul 07 07:32:24 2017
       Last Success Operation End: Fri Jul 07 08:28:05 2017
             Last Operation Begin: Wed Aug 16 11:22:59 2017
               Last Operation End: Wed Aug 16 11:22:59 2017
              Last Operation Size: 0B
             Last Operation Error: Metafile does not exist

This is most often seen in SnapVault volumes, but can be encountered on any volume with deduplication enabled.