On a host running multiple VMs, overcommitting memory is possible due to which capability?

• A. Memory Bursting
• B. Ballooning
• C. Swap
• D. Transparent Page Sharing

Answer: (A)

Memory bursting is the ability that makes memory overcommitment possible by allowing the hypervisor to grant more memory to virtual machines than there is physical RAM, then reclaim it as needed. When workloads vary, the hypervisor can allocate extra memory to VMs and rely on mechanisms inside the guests and the host to pull that memory back when another VM needs it. Ballo o n ing inside the guest OS inflates to mark pages as reclaimable, letting the hypervisor reclaim those pages without forcing the VM to swap, while transparent page sharing reduces the overall physical memory footprint by deduplicating identical pages across VMs. Swap may come into play under heavy pressure, but the essential capability enabling overcommitment is the dynamic, on-demand memory bursting supported by these memory-management techniques.