ESXi upgrade pre-check warning states boot LUN device may not be large enough for future install or upgrade

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

Preparing to upgrade ESXi shows warning message below.

• "The boot device of the host has a capacity of <xxxx> MiB. Install or upgrade to future ESXi releases will not be supported on this boot device. Please switch to a boot device that is at least <xxxx> MiB in size. Refer to KB-96511 for further details."

Cause

Minimum boot device size for upgrading ESXi is 8 GB. (ESXi 7 Hardware Requirements and ESXi 8 Hardware Requirements)

Resolution

The warning is valid, but should not keep the ESXi host from successfully upgrading.

 

Test if able to successfully upgrade an ESXi host. If it succeeds, there should be no need for any change to the boot LUN size, unless that LUN is running out of available space.

• If in the future the boot LUN size needs to be increased, do the following.

  • Simply increase the LUN size on the storage array side, as the warming message should be related to the size of the LUN and not the ESXi boot partitions on the LUN. During the upgrade of ESXi, if any changes need to happen for the boot partitions, those changes should happen automatically.