Simple definition
VMware memory compression stores some reclaimable guest memory in compressed host RAM to reduce swapping to disk.
Purpose and use
VMware memory compression can reduce the physical memory required for selected pages before they are moved to disk.
How does it work?
The hypervisor retains compressible pages in a cache and decompresses them when needed.
Example and verification
Review compression alongside ballooning, swapping and application latency to assess memory pressure.
Points to watch
Not every page compresses effectively, and compression uses processor resources.
In short
Compression manages pressure rather than replacing adequate RAM capacity.