Which technology in vSphere 6 allows identical memory pages to be shared among virtual machines to optimize memory consumption?

Transparent Page Sharing is a feature in VMware vSphere 6 that optimizes memory usage by allowing identical memory pages to be shared among virtual machines. This technique operates at the hypervisor level and works by finding duplicate memory pages across different VMs and consolidating them into a single physical page. This results in reduced memory consumption across the host by effectively reclaiming and utilizing memory resources.

When multiple virtual machines are running similar operating systems or applications, there’s a high chance that they will have identical memory pages. Transparent Page Sharing detects these duplicate pages and enables them to share the same physical memory location within the host. This optimization reduces the overall memory footprint required by the virtual machines and can lead to significant cost savings and improved performance.

The other technologies mentioned serve different purposes. Memory Compression is used to compress memory pages that cannot be actively shared, while Idle Memory Tax concerns the redistribution of the memory used by virtual machines that are idle. Ballooning is a mechanism that reclaims memory from running virtual machines by using a driver called the balloon driver, which can inflate and deflate its balloon to free up physical memory from VMs. While all these techniques contribute to memory management, Transparent Page Sharing specifically targets identical memory page consolidation.