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Upgrading a large cluster is a significant undertaking, likely involving down time and definitely requiring thorough planning and communication.
Non-disruptive upgrades (NDUs) allow a cluster administrator to upgrade the storage operating system while their end users continue to access data without error or interruption. Updating the operating system on a OneFS powered cluster is a simple matter of a rolling upgrade. During this process, one node at a time is upgraded to the new code, and the active NFS and SMB3 Continuous Availability (CA) clients attached to it are automatically migrated to other nodes in the cluster. Partial upgrade is also permitted, whereby a subset of cluster nodes can be upgraded. The subset of nodes may also be grown during the upgrade.
OneFS also supports upgrade rollback. This feature provides the ability to return a cluster with an uncommitted upgrade to its previous version of OneFS.
As part of an upgrade, OneFS automatically runs a pre-install verification check. This verifies that the configuration in your current installation of OneFS is compatible with the version of OneFS that is intended for the upgrade. When an unsupported configuration is found, the upgrade is stopped and instructions on troubleshooting the issue are displayed. Proactively running the pre-installation upgrade check before starting an upgrade helps to avoid any interruption due to incompatible configuration.
At around 30 minutes per node, rolling firmware upgrades of extra-large clusters are undesirable most of the time due to the duration. Instead, most customers prefer to schedule a maintenance window and perform a full cluster reboot.
An active MediaScan job that is running concurrently with a drive firmware update can significantly impact the performance on the cluster. To avoid this, pause any running MediaScan job before starting the firmware update process using the ‘isi job pause mediascan’ CLI command.
Further information about updating OneFS and firmware is available in the Upgrade Planning and Process guide.