iSCSI connection is lost after system board replacement

Applies to

• ONTAP Prior to 9.4
• Converged Network Adapter (CNA) ports
• ISCSI
• Motherboard replacement
• MTU 9000

Issue

• After replacing the system board:
  • Target LIF is not pingable
  • iSCSI connection is lost
  • Port MTU size got changed to 1500
  • EMS appears error message following

[?] Sat Jan 22 21:15:15 JST [node-2: vifmgr:callhome.clus.net.degraded:alert]: Call home for CLUSTER NETWORK DEGRADED: Large MTU Packet Loss - Ping failures detected between Cluster-1 ( AAA.AAA.AAA.AAA ) on node-2 and Cluster-2 ( BBB.BBB.BBB.BBB ) on node-1

• Node-1 and node-2 were configured as follows:

node-2：node-2 e0a（AAA.AAA.AAA.AAA）<-->Node-1：node-1 e0b（BBB.BBB.BBB.BBB）
node-1　e0a／e0b　MTU 9000 ⇒ 1500 (replaced MB)
node-2　e0a／e0b　MTU 9000