Network & Infrastructure / Storage Networks & Distributed Data
Storage multipath independence beyond two logical sessions
A server has two storage sessions but loses both during one switch reboot. Both logical paths may share the same physical NIC, switch or upstream power dependency.
Environment and inputs: Ceph and storage transport dependencies; match health identifiers and recovery behavior to the installed release. Diagnostic/design example; not tested on production equipment.
Collect the evidence
Map each initiator session through NIC, cable, fabric, target port and controller. Include VLAN and bond relationships so a logical path count is not mistaken for physical independence.
Explain the result
Multiple sessions provide useful redundancy only against failures outside their shared dependencies. A common switch or controller can collapse both paths despite an apparently healthy multipath summary.
Plan the fix
Design and document independent paths according to the storage platform's supported architecture. Remove hidden shared dependencies or explicitly accept and monitor the residual risk.
Check the result and rollback
Exercise one physical dependency at a time with application I/O and approved rollback. Restore the prior topology if path identity becomes ambiguous or the new arrangement violates supported target access behavior.