Upgrading AFM and AFM DR

Consider the following while upgrading Active File Management (AFM) or Active File Management - DR (AFM DR).

Before upgrading to a newer version of IBM Spectrum Scale, consider the version from which you are upgrading. IBM Spectrum Scale supports a limited form of compatibility with an earlier version between two adjacent releases and hence, coexistence and compatibility measures are required. For more information, see IBM Spectrum Scale supported upgrade paths. Limited with an earlier version compatibility allows temporarily operating with some IBM Spectrum Scale nodes that are running on the newer version, and some nodes that are running an earlier version. Within a cluster this enables you to perform an online upgrade to the new IBM Spectrum Scale version, if upgrade from your current version to the newer version is supported.

In AFM and multi-cluster environment, individual clusters can be upgraded at different schedules. Access to the file system data can be preserved even though some of the clusters might still be running on an earlier version. Home or the cache cluster must be upgraded independent of the other.

During an offline upgrade, the IBM Spectrum Scale service is interrupted. For an offline upgrade, you must shut down the cluster and suspend the application workload of the cluster. During an online upgrade, IBM Spectrum Scale service is not interrupted. In an online 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. You can also perform offline upgrades, if you can shut down the entire cluster. An offline upgrade is similar to the online upgrade procedure. As the entire cluster is offline, it is possible to upgrade to the latest code level instead of upgrading to an intermediate level, as might be required during an online upgrade.

Before you consider an online upgrade of the home or cache, ensure that:

The cluster is healthy and operational.
IBM Spectrum Scale is running on all nodes that are defined in the cluster.
All protocols that are defined on the protocol node are running.
Ensure that the storage at the cache cluster is adequate by using mmrepquota command during the home upgrade. Specifically, check the storage when the cache eviction feature is enabled for the storage management.

Cache cluster - In multiple gateway environment, gateway nodes can be upgraded one-by-one. In these cases, filesets that are associated with the gateway node to upgrade, are transferred to another gateway node, and any write-class operation triggers recovery feature that builds the queue on associated gateway node to continue processing the operations to home. Thus, cache to home are not disconnected, but some performance degradation can be seen due to another gateway node that is working for the connect for those filesets that are hosted on the upgrade node previously. In heavy load systems, transferring the filesets to another gateway node might have a performance impact. It is advised to choose a time for such upgrades where the load on the system or the number of data transfers is minimal.

Parallel data transfers enabled with GW mappings - in multiple-gateways environment, where parallel data transfer is enabled with multiple gateways, upgrading any of these mapped nodes results in a normal data transfer path.

Note: Fileset gateway relation or mapping might remain intact after upgrade, depending on the afmHashing version in use.

Home cluster - Cluster Export Services (CES) provides highly available file and object services to an IBM Spectrum Scale cluster by using Network File System (NFS), Object, or Server Message Block (SMB) protocols. With CES environment, the exports at home can be seen from cache by using the CES IP addresses. These IP addresses can align to protocol nodes when the CES node that already holds the CES IP address is shut down for an upgrade. The IP addresses alignment is according to the CES IP address distribution policies. Cache might see a short disruption at the time of CES failover at home but cache filesets continue to operate.

In a non-CES or NFS Server at Home environments, home to cache disconnects until the upgrade of NFS home server is complete. In a disconnected mode, cache builds up the queue for application operations. After Home is available, these operations are pushed to Home.

Note: You must shut down the NFS server before you issue the mmshutdown command on home nodes. When the IBM Spectrum Scale system upgrade is complete and the node mounts the file system, you can start the NFS server.

Note: The mmclone command is not supported on cache for AFM and primary for AFM DR. Clones that are created at home or secondary are replicated as different files. While upgrading to IBM Spectrum Scale 4.2.2 or later, the cache cluster must be upgraded before you consider upgrade of the home cluster.

Start of change The cache cluster and the home cluster can be upgraded by using the same method. If any of these cluster has protocol nodes, upgrade these nodes. For more information, see Online upgrade support for protocols and performance monitoring. End of change

Start of change After you completed upgrade, see Completing the upgrade to a new level of IBM Spectrum Scale. To know upgrade support for protocols and performance monitoring, see Online upgrade support for protocols and performance monitoring. End of change