Because vSAN is a kernel-based solution, upgrading vSAN requires upgrading the vSphere hypervisor. The VMware vSphere Update Manager (VUM) can be used to automate the upgrade process of hosts in a vSAN cluster. When upgrading, you can choose between two evacuation modes: Ensure Accessibility or Full Data Migration.
VMware Update Manager (VUM) builds recommendations for vSAN. Update Manager can scan the vSAN cluster and recommend host baselines that include updates, patches, and extensions. It manages recommended baselines, validates the support status from vSAN HCL, and downloads the correct ESXi ISO images from VMware.
vSAN 6.7 U1 performs a simulation of data evacuation to determine if the operation will succeed or fail before it starts. If the evacuation will fail, vSAN halts the operation before any resynchronization activity begins. In addition, the vSphere Client enables end users to modify the component repair delay timer.
vSAN 6.7 U3 includes an improved vSAN update recommendation experience from VUM, which allows users to configure the recommended baseline for a vSAN cluster to either stay within the current version and only apply available patches or updates, or upgrade to the latest ESXi version that is compatible with the cluster.
vSAN 6.7 U3 introduces vCenter forward compatibility with ESXi. vCenter Server can manage newer versions of ESXi hosts in a vSAN cluster, as long as both vCenter and its managed hosts have the same major vSphere version. Critical ESXi patches can be applied without updating vCenter Server to the same version.
vSAN 7.0 native File Services upgrades are also performed on a rolling basis. The file shares remain accessible during the upgrade as file server containers running on the virtual machines which are undergoing upgrade fail over to other virtual machines. During the upgrade some interruptions might be experienced while accessing the file shares.