Azure Stack HCI is a hyperconverged infrastructure (HCI) operating system that is delivered as an Azure service. HCI provides the latest security, performance, and feature updates at regular intervals. Updates are provided in the form of monthly quality updates and annual feature updates. The annual feature update is a major update and requires adequate resources and planning. Dell Engineering has worked with Microsoft on listing together prerequisites that should be considered and met before you update your Azure Stack HCI Solution, and also listed the different supported methods of updating your solution. We recommend that you go through this section before you decide which method to choose for updating your infrastructure.
- This activity should preferably be performed during off peak hours, as the upgrade process might require multiple CAU runs and heavy I/O on the subsystem will require long repair times.
- Ensure that the servers in use are in the compatibility matrix for support with the version of Azure Stack HCI that you intend to upgrade.
- Ensure that windows OS patches of 20H2 are upgraded at least to October 19, 2021 CU (KB5006741).
- Ensure that all nodes in the cluster are updated to the latest Windows operation system patches/hotfixes (Quality Updates) and hardware updates as per the latest support matrix/catalog. Drivers and firmware specific to the newer version of Azure Stack HCI OS, still have to be updated post upgrade.
- All nodes in the cluster should be available, up and running.
- The storage pool and all virtual disks should be healthy.
- Physical disks should not be in storage maintenance mode.
- If the cluster is a stretch cluster, see the section on "points to be noted for a stretch cluster" for further details.
- Any feature upgrade requires the CAU process to download large amounts of data to perform the upgrade. Usually it would be more than 2-3 GB.