DCUI displays less memory than installed

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:
The capacity on the ESXi DCUI console for memory info is less than the total installed physical memory.

For example, if you have installed 64 GiB of physical memory in the ESXi host, only 63.5 GiB is displayed on the ESXi DCUI screen.

Environment

VMware vSphere ESXi 6.5
VMware vSphere ESXi 5.1
VMware vSphere ESXi 5.5
VMware vSphere ESXi 6.7
VMware vSphere ESXi 6.0

Cause

Note: In general, the DCUI displays the approximate amount of memory that is available to ESXi.

This issue occurs when:

• A significant amount of memory may be reserved by system's firmware and thus not available to ESXi.
  
  For example, your system may have 64 GiB of memory installed, of which only 63.5 GiB is available to ESXi. The remaining memory is reserved by the machine's firmware. In this case DCUI displays 63.5 GiB Memory.
  
  
• The DCUI truncates values to one decimal place instead of rounding.
  
  For example, if your system has 4.0 TiB of installed memory, of which 3.999 TiB is available to ESXi, the DCUI displays 3.9 TiB Memory.

Resolution

This is an expected behavior.