Some memory pages may be compressed when reverting a VM from a memory snapshot

Products

• VMware vSphere ESXi

Issue/Introduction

When reverting a memory snapshot, swap and zipped values may be observed in the memory statistics. 
However, during reverting it, the memory usage of the ESXi  does not spike and the ballooning is not activated yet. 

Environment

VMware vSphere ESXi

Cause

This is a rare behavior by the ESXi design that may occur when reverting memory snapshots.

Resolution

This is expected behavior and not a product defect.
This behavior is specific to memory snapshots and does not occur with offline snapshots