Hi. I've implemented thin provisioing for a customer's VMWare VMFS datastore LUNS. Everything in the beginning was working as expected. The space that was actually being written to (i.e. add a 30GB VM to the datastore) was being reflected on the filer. I could see this through the following command:

aggr show_space -g

The allocated and used space would be identical - as expected. Now, let's say I created that thin provisioned LUN to be 350GB. ESX would think it's getting a 350GB LUN and my space used on the filer would state 0% used. It's only as I start adding VM's does this increase the %used space...fine.

Now, let's say I've added enough VM's that the entire 350GB is used up. When I run the aggr show_space command I see 350GB allocated, 350GB used - that's fine.

Now, I vmotion a bunch of VM's from that datastore to a different datastore, leaving 100GB of VM's on the original datastore. If I take a look at the ESX datastore I now see that out of the 350GB allocated, I have 100GB used and 250GB free - nice. BUT, when I take a look at the filer and run the aggr space_show -g, I still see 350GB allocated, 350GB used - even though from a VMFS perspective this is not the case.

I'm assuming this is the same issue that I've faced before with WAFL not knowing what's happening within VMFS when VMFS frees up space. WAFL doesn't own the VMFS so it can't reflect the changes that VMFS makes when it "deletes/moves" files.

The Space Reclaimer is a nice tool that is used within Snapdrive to reclaim blocks that have been "freed", essentially passing this information to WAFL so it knows how to update the space metrics. My question (and my client's question) is how do I reclaim that space on the filer AFTER the thin provisioinmed LUN has reached a certain size and then decreases - either because a VM was destroyed or a vmotion moved it to another datastore. It would be nice if there was some Space Reclaimer feature within ESX whereby I could either manually invoke or schedule it to run against a VMFS datastore.

I know that there is now the Virtual Storage Console - a vCenter snap-in. I wonder if space reclaimer could be added to that? Seems like the perfect place to put it.

Does anyone have any suggestions as to this dilema?

Thanks