This post came about after a brief discussion with my pal, Lee Dilworth. Although the outcome of this test has really nothing to do with vSAN, the behaviour was observed on certain Guest OS which were running on vSAN. I guess the first thing that needs to be made clear is that there is no support for in-guest UNMAP (or TRIM) for VMs running on vSAN at this time, although it is something we are examining very closely. So with this in mind, we had feedback to say that a test being run as part of a proof-of-concept was showing…