PowerScale OneFS Upgrade Planning and Process Guide

Rolling upgrades

A rolling upgrade installs the new operating system and restarts each node individually in the OneFS cluster so that only one node is offline at a time. A rolling upgrade takes longer to complete than a simultaneous upgrade. During a rolling upgrade, nodes that are not currently being upgraded remain online and can continue serving clients. However, clients that are connected to a restarting node are disconnected and reconnected. How the client connection behaves when a node is restarted depends on several factors including client type, client configuration (mount type, timeout settings), IP allocation method, and how the client connected to the cluster.