If I mechanically replace the words "routing mesh" with "load balancer", I instantly know what they're talking about without losing out on any important details.
Other than the fact that a load balancer is generally a monolithic piece of hardware. The failure modes are well defined, but most of them result in catastrophic outages.
I'm going to assume their routing mesh has many points of ingress and a larger number of exit paths (the dyno manifold), but that the nodes they've got participating in the mesh are actually in some sort of mesh topology (or form a connected graph).
This has the upside that if you lose several nodes in the mesh you probably haven't lost a path to any dynos. If you lose a whole AZ you can spin up new dynos in one of the existing ones and reconfigure the mesh quickly. My experience with loadbalancers, especially big load balancers is that updating a large swath of VIPs is NOT a fast operation (although you would start failing health checks on the missing nodes pretty quickly, adding new capacity to replace them is hard).
The mesh has the downside that the failure modes are a lot more complicated. Oh, and nobody knows what the hell you're talking about.
Of course, I could be wrong. They could just be using NetScalers (or ELB) and calling it a "routing mesh".
Oh, and nobody knows what the hell you're talking about.
Yes. It's a level of detail that borders on obfuscation.
fwiw, I've always used the term "load balancer" to also refer to two redundant load balancing machines. (If I worked with more complex load balancers, I doubt I'd stop.) In the general sense, it just means "the apparatus that balances the load".
I'm going to assume their routing mesh has many points of ingress and a larger number of exit paths (the dyno manifold), but that the nodes they've got participating in the mesh are actually in some sort of mesh topology (or form a connected graph).
This has the upside that if you lose several nodes in the mesh you probably haven't lost a path to any dynos. If you lose a whole AZ you can spin up new dynos in one of the existing ones and reconfigure the mesh quickly. My experience with loadbalancers, especially big load balancers is that updating a large swath of VIPs is NOT a fast operation (although you would start failing health checks on the missing nodes pretty quickly, adding new capacity to replace them is hard).
The mesh has the downside that the failure modes are a lot more complicated. Oh, and nobody knows what the hell you're talking about.
Of course, I could be wrong. They could just be using NetScalers (or ELB) and calling it a "routing mesh".