Cormac Hogan wrote a good article, VAAI-NAS – Some snapshot chains are deeper than others. The blog post highlights some of the differences between vendors and the impact of their decisions.
Nutanix doesn’t have a max chain depth. If you want to take 50,000 snaps, go knock yourself out. Nutanix performs a background copy block map operation after a snapshot is created, which effectively nullifies the effect of having a snapshot chain. This makes the inherited metadata available in the child’s metadata space itself, instead of having to traverse the snapshot chain upwards to find it. So there’s no overhead of doing IO on a child whether it is at level 5 or level 50,000.