Configuring Reliable Memory in Per-virtual machine basis

Products

• VMware vSphere ESXi

Issue/Introduction

The article provides steps to configure Reliable Memory on a per-virtual machine basis.

 

Reliable Memory is an unique feature introduced in vSphere 5.5. If the server platform supports the Reliable Memory feature, ESXi can put the memory pages consumed by critical services onto more reliable memory regions.

 

vmkernel and monitor are categorized as priority 0 so the memory pages consumed by them are on high priority to be put in the reliable memory area. Some system processes running on ESXi userworld are marked as memreliable and are categorized as priority 1. Therefore, they are a secondary priority to be put in reliable memory regions.

 

To protect guest VMs from memory failure, it is possible to place the memory pages consumed by virtual machines on the reliable memory area. This is done by configuring a VMX parameter. Memory pages consumed by virtual machines are categorized as Priority 2 so are a tertiary priority to be put in reliable memory area.

Environment

VMware vSphere ESXi 5.5
VMware vSphere ESXi 6.0
VMware vSphere ESXi 7.0
VMware vSphere ESXi 8.0

Resolution

VMX option sched.mem.reliable is enabled to place the memory pages consumed by a virtual machine into a reliable memory area. This option is on a per-virtual machine basis. The default value is FALSE.

 

To turn on the feature:

1. Edit the .vmx file using a text editor
2. Add the parameter:
   sched.mem.reliable = "True"
   
3. Save and close the file

Note: sched.mem.reliable is a flag to prefer reliable memory. It is not guaranteed that all memory pages consumed by the virtual machine are allocated from reliable memory regions.

To turn off the feature:

1. Edit the .vmx file using a text editor
2. Add the parameter:
   sched.mem.reliable = "False"
   
3. Save and close the file

Note: The vSphere Reliable Memory feature only works on server platforms for which the hardware supports Reliable Memory technology. Please contact the hardware vendor for questions about Reliable Memory technology.

Additional Information

Tips for editing a .vmx file