What does Memory Compression in vSphere 6 do with memory pages that can be compressed by at least 50 percent?

Memory Compression in vSphere 6 is a feature that enhances the management of a virtual machine's memory by taking advantage of free memory resources on the host. When memory pages can be compressed by at least 50 percent, this mechanism allows for efficient use of existing memory resources without needing to swap those pages to disk, which can slow performance.

By placing these compressible memory pages into a compressed memory cache, vSphere allows the virtual machine to retain more memory without increasing its physical memory footprint. This allows for higher performance and faster access to frequently used data since accessing compressed memory is much quicker than retrieving data from disk storage.

This process helps reduce the overall memory demand and improves the performance of virtual machines because compressed pages can be quickly decompressed and utilized when needed. Instead of the other options which involve moving data off the memory to slower storage solutions or transferring data to another machine, focusing on an in-memory approach through compression optimizes resource utilization effectively.