Volume Not On Preferred Path (VNOPP) is a condition that is observed on the storage in the Recovery Guru and in the Major Event Log (Event Type 4011). This condition is reported when a volume, or multiple volumes are owned by their non-preferred controller for a period of time that exceeds the Failover Alert Delay timer (default 5 minutes).
VNOPP is commonly caused by, but not limited to, any of the following:
- Controller reboot (example, PANIC, manual reset, Ancient IO, WDTO).
- Non-existent connection to a volume's owning controller.
- Misconfigured host mappings.
- A break in connection/instability in the SAN between a Host and the owning controller (example, Bad cable, bad SFP, bad HBA port, switch port bounce).
- Improperly configured SAN Host multipath.
This article provides a systematic approach to identify what caused a VNOPP, fix the underlying issue (if necessary), and reassign the volume(s) back to their preferred owner.
Note: DO NOT recommend upgrading controller firmware to fix volumes not on preferred path issue. Upgrading while the system is not stable can result in unpredictive behavior including outages.