Online upgrade support for protocols and performance monitoring

Online upgrade support for protocol nodes depends on which services have been enabled and deployed. Different protocol services have different levels of online upgrade support.

• NFS: Having different versions of NFS on protocol nodes in the cluster during the course of a node-at-a-time online upgrade can be tolerated.
• SMB: All protocol nodes running the SMB service must have the same version installed at any time. In addition to a brief outage of the SMB service, this also requires a brief outage of the NFS service in case Active Directory (AD) authentication is being used. SMB upgrade in an IBM Spectrum Scale cluster is done in two phases. The protocol nodes in the cluster are divided in two halves and SMB is upgraded on each half one by one.
• Object: Because object operations interact with all nodes, all object nodes must be at the same level. Therefore, object services need to be stopped across the cluster for the duration of the upgrade. Other protocol services can continue to be run.
• Performance monitoring: Having two different versions on collector nodes will result in a loss of communication and could potentially result in missing performance metrics until collector versions match. This limitation is not applicable if the source and the target versions are later than 5.0.1.