(contributor here) At my company our proprietary database layout is based on Arrow. Our workload is analytical and we are using it for read mostly workloads.
As landing page states it is a runtime supplies actor-model like concurrency. If you are familiar with Erlang. Bastion is the reflection of the Erlang runtime in Rust. Far beyond an actor system implementation. It is a complete system with full asynchronous communication.
"...It supplies actor-model-like concurrency with a lightweight process implementation and utilizes all of the system resources efficiently guaranteeing of at-most-once message delivery."
It might be a single process, pile of workers, a bunch of http servers dispatching requests, various middleware layers connected with asynchronous boundaries. With all these built on top of crash and fault recovery.
Worth to mention that Bastion has been developed a lot and it has its own design(in simple terms SMP based executor) to leverage asynchronous programming (with fault-tolerant manner). It isn't dependent on any runtime. You can mix and use any runtime with it and supplies hierarchical reduction based concurrency.
We proudly take Erlang's runtime model and implemented it in Rust. Moreover, we are currently working on distributed carrier protocol to make Bastion form a cluster, exchange data and recover from partial failures in distributed workloads too.
Local failures are recovered and we have built-in lifecycle management.