Rolling upgrades

During a regular upgrade, the IBM Spectrum Scale service is interrupted. For a regular upgrade, you must shut down the cluster and suspend the application workload of the cluster. During a rolling upgrade, there is no interruption in the IBM Spectrum Scale service. In a rolling upgrade, the system is upgraded node by node or failure group by failure group. During the upgrade, IBM Spectrum Scale runs on a subset of nodes.

In a rolling upgrade, nodes from the same failure group must be upgraded at the same time. If nodes from two or more failure groups stop functioning, only a single data copy is available online. Also, if the quorum node stops functioning, the quorum relationship in the cluster is broken. Therefore, the quorum node must be excluded from the rolling upgrade of the failure node.