FoundationDB does not offer locale-aware replication in the sense you are using the term. The closest it has it something like the
three_datacenter mode where it makes sure that everything is stored in three different data centers, which allows for solving the problem of “I want to be able to survive a datacenter going down and not lose availability or durability”. (It is locale aware in that it chooses locations to place your data while keeping the locale in mind.) It doesn’t have something like “store these data (about my eastern US customers) in this (eastern US) datacenter and these data (about my western US customers) in this (western US) detacenter”.
As @ryanworl alludes to, if you wanted to do something like separate your data like that, you would still have to do something like have one FDB cluster per region or per DC, so you could use FDB clusters as the building block, but it doesn’t work like that out of the box.
That being said, FoundationDB does allow you to specify locality information about your clients and servers that can allow for things like “DC-aware” queries. In particular, you need to set the
--locality_datacenter_id and (for good measure)
--locality_machine_id command line arguments to fdbserver. Then if you also call
set_machine_id on all of your clients, then any client who sees that there is data available from its own datacenter (or machine if you sometimes run clients and servers on the same machine) will use that one if available. This doesn’t help with commit latencies (or with get-read-version latencies…), but it can be useful for making reads significantly faster in multi-DC configurations.
So, if your use case were instead, “I have one global DB that I want to be able to query from multiple DCs with only single-DC latencies,” then FDB could probably do it, though you’d still be putting the data everywhere.
I will also say that a lot of our multi-DC story gets better in 6.0 (with more work to make more things DC-local so most things are LAN latencies rather than WAN latencies). There is still some work to this affect currently on the 6.1 milestone: https://github.com/apple/foundationdb/issues/323