Skip to content

Symptoms: LACP Mismatch / One Link Hot

  • Server db-prod-02 has a 2x10G LACP bond (bond0) to the top-of-rack switch for redundancy and throughput.
  • Monitoring shows bond0 reports both links (eth2, eth3) as UP and active.
  • However, network graphs show nearly 100% of traffic flowing over eth2 and almost none on eth3.
  • During peak hours, eth2 saturates at 10Gbps causing packet drops and microbursts, while eth3 sits idle.
  • Application teams report intermittent latency spikes and occasional TCP retransmits during peak load.
  • The server NIC bonding was configured by the Linux team; the switch port-channel was configured by the network team.
  • Both teams confirm their side "looks fine."
  • The bond mode on the server is set to 802.3ad (LACP) with xmit_hash_policy layer3+4.