Should new Linux VMs under ESXi 5.5 mount their filesystems with discard option?
Solution 1:
As far as I know ESXi doesn't make use of TRIM commands from a VM. I havn't found anything definite or official from VMware but in a comment to a blog post I found this:
In VMs TRIM is definetely not available, I already checked that.
FAQ: Using SSDs with ESXi
So it looks like mounting filesystems with the discard option won't help you.