Troubleshoot flapping cluster network ports e0a e0b in AFF-A300 FAS8200

Applies to

• TNSC (Two node switchless cluster) HA pair
• AFF A300 / FAS8200

Issue

• In autosupport

HA Group Notification (CLUSTER NETWORK DEGRADED) ALERT

• In EMS logs

kernel: netif.linkDown:info]: Ethernet e0b: Link down, check cable.
vifmgr: vifmgr.portdown:notice]: A link down event was received on node node-01, port e0b.
vifmgr: vifmgr.clus.linkdown:EMERGENCY]: The cluster port e0b on node node-01 has gone down unexpectedly.
vifmgr: vifmgr.lifmoved.linkdown:notice]: LIF node-01_clus2 (on virtual server 4294967293), IP address 169.254.250.110, is being moved to node node-01, port e0a.
vifmgr: vifmgr.lifsuccessfullymoved:notice]: LIF node-01_clus2 (on virtual server 4294967293), IP address 169.254.250.110, is now hosted on node node-01, port e0a.
kernel: netif.linkUp:info]: Ethernet e0b: Link up.
vifmgr: vifmgr.portup:notice]: A link up event was received on node node-01, port e0b.
vifmgr: rdb.ha.synchronized:notice]: Entering HA-Normal: Synchronized with peer in a high-availability (HA) configuration
vifmgr: callhome.clus.net.degraded:alert]: Call home for CLUSTER NETWORK DEGRADED: Frequent Link Flapping - Cluster port e0b on node node-01 has experienced multiple link down notifications

• In ifstat of the cluster ports show increasing errors of CRCs, error/illegal symbol

::> run -node <node_name> -command ifstat e0a (or e0b)

-- interface  e0b  (197 days, 22 hours, 28 minutes, 36 seconds) --
RECEIVE
 Total frames:    40278m | Frames/second:       0  | Total bytes:       104t
 Bytes/second:        0  | Total errors:     1369k | Errors/minute:       0
 Total discards:      0  | Discards/minute:     0  | Multi/broadcast:  1422k
 Non-primary u/c:     0  | CRC errors:       1368k | Runt frames:         0
 Fragment:            1  | Long frames:         0  | Jabber:            236
 Length errors:     636  | No buffer:           0  | Xon:                 0
 Xoff:                0  | Pause:               0  | Jumbo:           12467m
 Noproto:             0  | Error symbol:    25630  | Illegal symbol:  13756
 Bus overruns:        0  | Queue drops:         0  | LRO segments:    32502m
 LRO bytes:         103t | LRO6 segments:       0  | LRO6 bytes:          0
 Bad UDP cksum:       0  | Bad UDP6 cksum:      0  | Bad TCP cksum:       0
 Bad TCP6 cksum:      0  | Mcast v6 solicit:    0  | Lagg errors:         0
 Lacp errors:         0  | Lacp PDU errors:     0
TRANSMIT
 Total frames:    45345m | Frames/second:       0  | Total bytes:       272t
 Bytes/second:        0  | Total errors:        0  | Errors/minute:       0
 Total discards:   3416  | Queue overflow:   3416  | Multi/broadcast:  1415k
 Collisions:          0  | Xon:                 0  | Xoff:                0
 Pause:               0  | Jumbo:           13190m | Cfg Up to Downs:     2
 TSO non-TCP drop:    0  | Split hdr drop:      0  | Timeout:             0
 TSO segments:    11438m | TSO bytes:         259t | TSO6 segments:       0
 TSO6 bytes:          0  | HW UDP cksums:       6  | HW UDP6 cksums:      0
 HW TCP cksums:   25648m | HW TCP6 cksums:      0  | Mcast v6 solicit:    0
 Lagg drops:          0  | Lagg no buffer:      0  | Lagg no entries:     0
DEVICE
 Mcast addresses:     2  | Rx MBuf Sz:       4096
LINK INFO
 Speed:               0  | Duplex:            full | Flowcontrol:       none
 Media state: no carrier | Up to downs:          9 | HW assist:        7711