Memory Tiering Performance in VMware Cloud Foundation 9.0

Memory costs continue to be one of the largest components of server infrastructure spending, yet much of that expensive DRAM sits underutilized. What if you could double your VM density and cut total cost of ownership by up to 40%?

With VMware Cloud Foundation 9.0, that's exactly what Memory Tiering delivers. Today, we're excited to share performance testing results that demonstrate how this technology is transforming datacenter economics in a new performance study: Memory Tiering Performance in VMware Cloud Foundation 9.0.

In this blog, we highlight performance results from the paper, which show that Memory Tiering enabled a 2x increase in VM density with only a slight impact to performance. For full details on how memory tiering works and more in-depth performance information, please refer to the paper.

How Memory Tiering improves datacenter performance while reducing cost

In VCF 9.0, Memory Tiering presents a single logical memory space for VMs. Under the hood, however, it manages the Tier 0 (DRAM) and Tier 1 (Memory Tiering) memory types based on VM memory activity. Essentially, it works to keep active "hot" memory on DRAM and inactive "cold" memory on NVMe.

From the VM's perspective, this appears as a single, larger memory space. Behind the scenes, ESX dynamically manages the placement of memory pages across the two tiers: DRAM and NVMe. This ensures optimal performance.

We conducted testing across different enterprise workloads to validate Memory Tiering performance. We used both Intel and AMD servers with various DRAM configurations. The default DRAM:NVMe ratio is 1:1 for VCF 9.0. We used this default 1:1 ratio for all tests.

Login Enterprise: Virtual desktop performance

We used Login Enterprise to test VDI performance in several different scenarios. In all tests, we were able to double the number of VMs on the ESX host with minimal performance impact. For example, on a 3-node vSAN cluster configuration:

• We doubled the number of VDI sessions that could run on a 3-host vSAN cluster from 300 (DRAM only) to 600 (Memory Tiering).
• There was no performance loss compared to an equivalent all-DRAM configuration.

VMmark 3.1: Enterprise application performance

VMmark 3.1, which consists of multiple workloads representing a set of enterprise applications, demonstrated excellent results:

• The Memory Tiering configuration achieved 6 tiles vs 3 tiles in the DRAM-only configuration. This is a 2x improvement.
• When we compared 1TB DRAM only vs 1TB Memory Tiering, the performance loss was only 5% despite Memory Tiering using slower NVMe.

HammerDB and DVD Store: Database performance

Database performance is often the most demanding test for any infrastructure. We used both HammerDB and DVD Store as workloads to test SQL Server, Oracle Database, and MySQL. Using Memory Tiering, we were able to double the number of VMs with minimal performance impact. For example, Oracle Database with a DVD Store workload showed the following:

• We were able to run 8 VMs on an ESX host with Memory Tiering vs 4 VMs in a DRAM-only configuration-doubling the density.
• We observed less than 5% performance loss when comparing 1TB DRAM and 1TB Memory Tiering configurations.

Monitoring Memory Tiering on ESX hosts

You should monitor two key metrics to ensure good performance with Memory Tiering:

• Keep active memory at 50% or less of DRAM for optimal performance.
  
• Monitor the NVMe device read latency. You'll get the best performance below 200 microseconds.
  

Transform your datacenter economics

Memory Tiering gives a new take on memory provisioning:

• It can offer up to a 40% TCO savings through reduced DRAM requirements.
• It works transparently with no application or guest OS changes.
• It can achieve 2x VM density increases across diverse workload types.
• It works within a flexible infrastructure that adapts to changing workload demands.

Memory Tiering is available now in VMware Cloud Foundation 9. Download the complete performance study to dive deep into our testing methodology, detailed performance results, and implementation best practices.

Ready to get hands-on with Memory Tiering?

A comprehensive Hands-on Lab provides you with a live vSphere 9.0 environment where you can explore Memory Tiering and learn how the use of NVMe drives can enhance and optimize the amount of memory available to ESX hosts.

Learn more

• Memory Tiering Performance in VMware Cloud Foundation 9.0 performance study
• What's New in VMware Cloud Foundation 9.0? blog post
• Memory Tiering over NVMe user guide
• VMware Cloud Foundation product page
• Contact Sales form