The ONTAP pre-upgrade health check (cluster image validate) is designed to prevent upgrades on clusters with underlying issues that could cause disruption or data loss.

A hot spare in use indicates that a disk has failed and an aggregate is in a degraded state while it reconstructs. Upgrading a system with a degraded aggregate is a high-risk operation and is therefore blocked by the pre-check.

A volume (LUN) on a non-preferred path indicates a SAN multipathing or configuration issue. During a non-disruptive upgrade, controllers perform takeovers and givebacks. If paths are not configured correctly, hosts can lose connectivity to their LUNs during this process. This is flagged as an error to ensure host connectivity is maintained.

C. An excess number of event log events is not a direct failure condition. The specific content of critical events, not the quantity, would cause a failure.

D. ONTAP upgrades are designed to be non-disruptive (NDU). The system is expected to be processing I/O during the entire upgrade process.

1. NetApp ONTAP 9 Documentation

"ONTAP upgrade and revert/downgrade guide": In the section "Preparing for the upgrade

" it is stated that you must "verify that the cluster and all nodes are healthy." A system with a spare in use (degraded aggregate) or multipathing errors (non-preferred path) is not considered healthy. The cluster image validate command enforces these health requirements.

2. NetApp ONTAP 9 Commands Manual Page Reference

cluster image validate: The documentation for this command lists the specific validation checks performed. These checks include spare-low (which would be triggered by a spare in use) and lun-maps-not-on-preferred-path. Both are listed as checks that result in an "Error" severity

which fails the pre-upgrade validation.

3. NetApp Knowledge Base

Article ID 1030339

"Top 10 issues that cause ONTAP upgrades to fail": This article explicitly lists "Degraded Aggregates" and "SAN/LIF/Multipathing issues" as common and critical failures identified by pre-upgrade health checks. A spare in use leads to a degraded aggregate

and a non-preferred path is a primary multipathing issue.