VMware vSphere 7.x Memory Reclamation-Part 5: Memory Compression Cache

In this post, we are going to discuss about memory compression cache technique used by ESXi host. In previous posts we have already discussed TPS and ballooning. So compression is the next technique in order that gets initialized when ESXi host is under memory contention. ESXi provides a memory compression cache to improve virtual machine … Continue reading VMware vSphere 7.x Memory Reclamation-Part 5: Memory Compression Cache →

VMware vSphere 7.x Memory Reclamation-Part 1: Basics

Welcome everyone to this series on memory reclamation techniques in vSphere 7.x. This will be one more long series of posts after my previous series on uncovering virtual networking. In this series, we will try to understand the memory virtualization basics, memory reclamation techniques in vSphere (Specifically ESXi hosts), ESXi host Memory states, and sliding … Continue reading VMware vSphere 7.x Memory Reclamation-Part 1: Basics →

VMware Memory reclamation techniques run cycle in vSphere 6.x Part-1

Why Memory reclamation: ESXi supports memory over commitment in order to provide higher memory utilization and higher ratio of consolidation. In order to effectively support memory over commitment, the hypervisor provides efficient host memory reclamation techniques. ESXi uses several techniques to reclaim virtual machine memory, which are: Sliding scale Method Transparent page sharing (TPS) Ballooning … Continue reading VMware Memory reclamation techniques run cycle in vSphere 6.x Part-1 →

VMware memory reclamation vSphere 6: Mem.minfreepct and sliding scale method PART2

Before I talk about sliding scale method, let's discuss about mem.memminfreepct value. Eventually this discussion will lead us to understanding sliding scale method. What is mem.minfreepct value? MinFreePct determines the amount of memory that the VMkernel should keep free. This threshold is further subdivided in multiple memory thresholds i.e. High, Clear (New in vSphere … Continue reading VMware memory reclamation vSphere 6: Mem.minfreepct and sliding scale method PART2 →

VMware Memory Reclamation:Hypervisor Swapping PART6

ESXi employs hypervisor swapping to reclaim memory, if other memory reclamation techniques like ballooning, transparent page sharing, and memory compression are not sufficient to reclaim memory. Transparent Page Sharing (TPS) speed is dependent of possibility to share memory pages, another reclamation technique of ballooning also depends on guest operating system response for memory allocation. Due … Continue reading VMware Memory Reclamation:Hypervisor Swapping PART6 →

VMware Memory Reclamation: Memory Compression Explained PART5

ESXi provides a memory compression cache to improve virtual machine performance when you use memory over commitment. If the virtual machine’s memory usage reaches to the level at which host-level swapping will be required, ESXi uses memory compression to reduce the number of memory pages it will need to swap out. Because the decompression latency … Continue reading VMware Memory Reclamation: Memory Compression Explained PART5 →

Memory Reclamation-Ballooning PART4

Ballooning in simple terms is a process where the hypervisor reclaims memory back from the virtual machine. Ballooning gets initiated when the ESXi host is running out of physical memory. The demand of the virtual machine is too high for the host to handle.But before I describe Ballooning, it is good idea to understand why … Continue reading Memory Reclamation-Ballooning PART4 →