25 - Performing a Rolling Upgrade

Abstract

One of the greatest maintenance benefits of TruCluster Server is the rolling upgrade. A rolling upgrade helps to update the operating system and the cluster software. There are three basic tasks that can be accomplished by performing a rolling upgrade: upgrading the base operating system and the cluster software from one version to the next, patching the current version of the operating system and cluster software, installing a New Hardware Delivery kit. A rolling upgrade of a cluster is accomplished through an ordered series of stages. Disk space requirements are an important issue during any rolling upgrade of a cluster. As a general rule, there should be at least 50 percent free space in the root file system. Preparing the cluster for the rolling upgrade includes several parts. Each of these parts must be completed before continuing to the next stage of the rolling upgrade. The “lead member” is chosen as the first member of the cluster to be rolled. New TruCluster Server software often takes advantage of the latest features that can only be found in the latest systems firmware updates from HP. During the Setup Stage, numerous subtasks are performed. The Setup Stage has been known to take a very long time—over two hours—on clusters greater than two cluster nodes. While the lead cluster member was upgraded during the Install Stage, upgrades to the remaining cluster members are performed during the Roll Stage. The Switch Stage is where any new software features are installed during the Install Stage. The final stage of Rolling Upgrade is Clean Stage.