[theojulienne]

Fastly's MAC-based solution to this was actually one of the existing implementations we read about back when designing the original implementation of GLB in 2015/16, along with Facebook's IPVS-based solution. We loved the ideas behind Fastly's model, but didn't want to mess with Layer 2 to do it. GLB Director took some inspiration from both designs in the creation of L4 second chance and the L4/L7 split design.

[gbrayut]

Thanks for the details! I'd love to hear more about any data you have on the efficiency of a "second chance" design vs expanding to three or more failover servers. Very curious if a single alternate is enough to cover majority of incidents (xxx out of 1000 events?) Or how frequently you see failures that fall outside the two chance design decisions.

Keep up the great work!