During a planned controller upgrade, NAS clients stay connected but iSCSI lose connectivity. Why does this happen?

During a planned controller upgrade, NAS clients stay connected but iSCSI lose connectivity. Why does this happen?

• A. iSCSI LIFs fail over only when manually triggered.
• B. SAN LIFs cannot fail over automatically.
• C. The system is out of LIF failover policies.
• D. NAS LIFs require multipathing while SAN does not.

Answer: (B)

The key idea is how LIF failover behaves for different protocols during maintenance. In a clustered NetApp environment, you can move logical interfaces (LIFs) to the surviving node to keep clients connected. NAS LIFs (used by NFS/SMB) are typically configured to fail over automatically, so when a controller is being upgraded, those LIFs can move to the other node and NAS clients stay connected, with clients reconnecting afterward. SAN LIFs (iSCSI) behave differently. They are not automatically moved during maintenance in many configurations, so the iSCSI LIFs stay attached to the node that’s being upgraded. Because the iSCSI target IP doesn’t migrate on its own, the iSCSI sessions on the initiators lose connectivity during the upgrade. To keep iSCSI paths up, you need to perform a manual failover of the SAN LIFs (move them to the other node) as part of the maintenance plan. So the observed behavior—NAS clients remaining connected while iSCSI loses connectivity during a planned upgrade—happens because SAN LIFs cannot fail over automatically, whereas NAS LIFs can.

The key idea is how LIF failover behaves for different protocols during maintenance. In a clustered NetApp environment, you can move logical interfaces (LIFs) to the surviving node to keep clients connected. NAS LIFs (used by NFS/SMB) are typically configured to fail over automatically, so when a controller is being upgraded, those LIFs can move to the other node and NAS clients stay connected, with clients reconnecting afterward.

SAN LIFs (iSCSI) behave differently. They are not automatically moved during maintenance in many configurations, so the iSCSI LIFs stay attached to the node that’s being upgraded. Because the iSCSI target IP doesn’t migrate on its own, the iSCSI sessions on the initiators lose connectivity during the upgrade. To keep iSCSI paths up, you need to perform a manual failover of the SAN LIFs (move them to the other node) as part of the maintenance plan.

So the observed behavior—NAS clients remaining connected while iSCSI loses connectivity during a planned upgrade—happens because SAN LIFs cannot fail over automatically, whereas NAS LIFs can.