So here we are with another post in this series. In previous post we discussed basics of memory virtualization concepts and the need for memory reclamation. In this post we will explore ESXi host memory states, sliding scale method of calculating Mem.MemMinFreePct. As discussed in previous post, multiple VMs that run on ESXi host, share … Continue reading VMware vSphere 7.x Memory Reclamation-Part 2: Mem.MemMinFreePct
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
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
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
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
On an ESXi host, Many ESXi workloads present opportunities for sharing memory across virtual machines (as well as within a single virtual machine). So instead of creating multiple duplicate pages in host memory for virtual machines, TPS is used to perform memory page sharing. In vSphere 6, intra-VM TPS is enabled by default and inter-VM … Continue reading Transparent Page Sharing (TPS) in vSphere 6.0 PART3
