vSphere 6.5 virtual NVMe does not support TRIM/UNMAP/Deallocate

I was playing with guest TRIM/UNMAP the other day and looked at new shiny virtual NVMe controller. While it would not help much in my workloads, cutting overhead never hurts. So I tried to do “defrag /L” in VM and it return that device doesn’t support it.

So I looked up release notes. Virtual NVMe device: “Supports NVMe Specification v1.0e mandatory admin and I/O commands”.

The thing is that NVMe part that deals with Deallocate (ATA TRIM/SCSI UNMAP in NVMe-speak) is optional. So back to pvscsi for space savings…