A node has failed.

For an automatic takeover to occur in an HA pair, the following conditions must be met:

The HA pair uses mailbox disks to coordinate and ensure that both nodes have consistent cluster state information.

If the mailbox disks are not reachable, the takeover process cannot proceed.

1. Mailbox Disks Must Be Reachable:

The nodes in an HA pair continuously mirror NVRAM data to ensure that writes are protected.

If NVRAM is not synchronized, the takeover cannot safely handle active workloads.

2. NVRAM Must Be Synchronized:

A. The combined utilization of both nodes must be less than 100%:

This is not a requirement for automatic takeover. ONTAP can handle higher utilization during failover scenarios.

B. The cluster network must be available:

While the cluster network is critical for normal operation, takeover can still occur if the cluster network is unavailable, as long as the HA interconnect is operational.

Why Other Options Are Incorrect:

NetApp "ONTAP High Availability Guide" outlines the requirements for automatic takeover in HA pairs.

"ONTAP NVRAM Synchronization and Failover Guide" explains NVRAM mirroring requirements.

References: