Network Bonding Modes
Swarm supports network port bonding modes (as supported by the Linux kernel):
active-backup (bonding mode 1)
balance-alb (bonding mode 6)
802.3ad (bonding mode 4)
Bonding mode 6 (balance-alb) is supported when using a single peer switch. For the requirements of using multiple switch chassis to provide switch layer redundancy, configure Swarm to use bonding mode 1 (active-backup). Choose bonding mode 4 (802.3ad) with further planning and testing.
Bonding mode 1 (active-backup) is advised for “out of the box” multi-switch and MLAG configurations, whereas bonding mode 4 (802.3ad) needs additional configuration on the switch side to function. Since failover and traffic balancing with MLAG is proprietary to switch vendors, it is necessary to review switch capability to determine the appropriate bonding mode for MLAG (i.e., bonding mode 1 or 4 i.e. active-backup or 802.3ad).
Using Multi-port NICs
Swarm bonds the NIC ports and detects and uses a single IP address for the bond definition.
Multiport network cards (two or more ports per card) are not considered fully redundant when used in Swarm storage hosts.
Multiport NICs experience common failure modes to disconnect a Swarm host. A true 'active-active' design includes the use of separate NICs in the storage hosts to meet that requirement.
PXE Boot in MLAG Configuration
PXE passthrough behavior is important in either an L2 or L3 MLAG configuration. Configuring nodes for network (PXE) boot when 802.3ad and MLAG are in place is difficult to use for such network configurations. Vendor implementation of PXE passthrough for MLAG behaves inconsistently, therefore, active-backup bonding mode is strongly advised in this scenario.