The specified item was not found. and the team in Support made me aware of a pretty cool new feature we've built into the VMware plugin as part of NimbleOS 3. Now when we spot that there are inefficiencies at the VMFS layer, the Nimble VMware plugin will now auto-notify you if you should run SCSI UNMAP to make the volume efficient / free up unused space in the volume, and it will even give you the command to run in the CLI . This can be found in the Datastore Summary page.
The current setting is for the alert to display when we deem the savings to be greater than 20%. This is not a tuneable parameter at the moment - look for that to change in the future.
We cannot allow for a "fix it" button to be presented to auto-run the command for you sadly - we're constrained by the VMware SDK for SCSI UNMAP. It can be automated using PowerCLI should you wish.
Not too sure what SCSI UNMAP is, or what the benefits are of running it? Matt Allford (on twitter as @mattallford) wrote an excellent blog on the benefits here: ESXi and Nimble Storage Unmap SCSI Blocks | Matt Alllford's Blog