I assume you (my reader) is familiar with LACP but do you know what LBT is? If not, here is the short explanation.
VMware LBT (load based teaming) is advanced switch independent teaming available on VMware DVS which pin each VM vNIC to particular physical uplink in roud robin fasion but if the network traffic of particular physical NIC is higher then 75% of total bandwidth over 30 seconds it will initiate rebalancing across available physical uplinks (physical NICs of ESXi host) to avoid network congestion on particular uplink.If you are not familiar with basic VMware vSphere networking read my previous blog post "Back to the basics - VMware vSphere networking" before continuing.
What we are doing is the comparison of switch independent teaming and LACP. LACP is the capability of VMware Distributed Virtual Switch (VDS), therefore, I would assume you are on vSphere Enterprise Plus license and having VDS. When you have VDS then I would have another assumption, that you are already considering LBT as it is the best choice for switch independent teaming algorithms available on VDS.
LBT versus LACP comparison
Option 1: Switch Independent Teaming (LBT - Load Based Teaming)
Option 2: LACP
- Fully independent on upstream physical switches
- Simple configuration
- Beacon probing can be used. Note, that beacon probing requires at least 3 physical NICs.
- Single VM cannot handle higher traffic then is the bandwidth of single physical NIC.
- One of the main LACP advantages is continuous heartbeat between two sides of the link (ESXi physical NIC port and switch port). VMware's LACP is sending LACPDUs every 30 seconds but it can be reconfigured to fast mode when LACPDUs are exchanged every 1 second. This improves failover in case of link failure and also helps when link status (up/down) do not work well.
- Single VM can, in theory, handle higher traffic then single physical NIC because of load-balancing algorithm.
- ESXi Network Dump Collector does not work if the Management vmkernel port has been configured to use EtherChannel/LACP
- VMware vSphere beacon probing cannot be used
When you do not have direct or indirect control of physical network infrastructure then switch independent teaming is generally much simpler and safer solution, therefore LBT is a better choice.
Relevant blog post on this topic "VMware vSphere DVS LACP timers".