iSCSI LUN access fails after node takeover

Applies to

• ONTAP 9.x
• Microsoft Windows Server
• iSCSI Multipath I/O (MPIO)

Issue

• After NodeA failure and NodeB takeover, LUN access is not possible.
• Both nodes have iSCSI LIFs created.
• No iSCSI request or session history after takeover, indicating no communication from the host.
• Access is restored after hardware replacement and giveback to NodeA.
• Host event logs show detection attempts for both LIFs, suggesting MPIO is configured but connection fails.

Event Log Entries:

Log Name:      System
Source:        MSiSCSI
Date:          7/23/2025 12:43:08 PM
Event ID:      113
Task Category: None
Level:         Warning
Keywords:      Classic
User:          N/A
Computer:      Computer.co.jp
Description:
iSCSI discovery via SendTargets failed with error code 0xefff0003 to target portal *192.168.1.A 0003260 ROOT\ISCSIPRT\0000_0.

Log Name:      System
Source:        MSiSCSI
Date:          7/23/2025 12:43:08 PM
Event ID:      113
Task Category: None
Level:         Warning
Keywords:      Classic
User:          N/A
Computer:      Computer.co.jp
Description:
iSCSI discovery via SendTargets failed with error code 0xefff0003 to target portal *192.168.1.B 0003260 ROOT\ISCSIPRT\0000_0.

Log Name:      System
Source:        MSiSCSI
Date:          7/23/2025 12:43:08 PM
Event ID:      121
Task Category: None
Level:         Warning
Keywords:      Classic
User:          N/A
Computer:      Computer.co.jp
Description:
The firewall exception to allow Internet Storage Name Server (iSNS) client functionality is not enabled. iSNS client functionality is not available.