Network & Infrastructure / Linux Networking & Host Performance
LACP bond members active but not in the same aggregator
A Linux host shows two up bond slaves, yet only one is usable or traffic fails unpredictably. The switch ports may not belong to the same compatible aggregation group.
Environment and inputs: Linux network namespaces, host routing and network drivers; availability and semantics depend on kernel and driver versions. Diagnostic/design example; not tested on production equipment.
Collect the evidence
Inspect bond mode, partner identity, aggregator membership, collecting/distributing state and switch configuration. Physical carrier and slave presence are insufficient to establish a working LACP bundle.
Explain the result
LACP negotiates aggregation compatibility and forwarding participation. Links attached to inconsistent partners or groups cannot be treated as one valid aggregate merely because both have carrier.
Plan the fix
Correct the coordinated switch and host bundle definition using the supported multi-chassis design where applicable. Avoid changing to an unrelated bonding mode to hide partner inconsistency.
Check the result and rollback
Test each member failure and multiple independent flows while monitoring aggregation state. Restore the prior single working path if the corrected bundle still loses packets or misidentifies its partner.