Increase your cluster density with Memory Tiering in Amazon Elastic VMware Service

This article explains how Memory Tiering in VMware Cloud Foundation 9.1 increases cluster density in Amazon Elastic VMware Service by using NVMe as a second memory tier.

• Memory Tiering uses dedicated NVMe devices as Tier 1 memory alongside DRAM (Tier 0), automatically tiering cold pages to NVMe when DRAM reaches ~80% capacity
• Supported on i4i.metal and i7i.metal-24xl instance types with default 1:1 DRAM-to-NVMe ratio, effectively doubling addressable memory
• Active memory (pages actively used by VMs) must stay below 50% of DRAM for optimal performance; consumed memory can double safely
• On Amazon EVS, NVMe capacity used for Memory Tiering is removed from vSAN datastore, requiring careful capacity planning and sufficient free vSAN space
• Activation involves removing NVMe drives from vSAN, then configuring Memory Tiering through vSphere Configuration Profiles with optional software mirroring for redundancy
• Deactivation reverses the process; hosts enter maintenance mode during configuration changes, typically non-disruptive

Memory Tiering enables cost-effective cluster consolidation by increasing effective memory capacity without adding hosts, provided active memory fits in DRAM and vSAN capacity is available.