## Problem
Storage controller upgrades (restarts, more generally) can cause
multi-second availability gaps.
While the storage controller does not sit on the main data path, it's
generally not acceptable
to block management requests for extended periods of time (e.g.
https://github.com/neondatabase/neon/issues/8034).
## Summary of changes
This RFC describes the issues around the current storage controller
restart procedure
and describes an implementation which reduces downtime to a few
milliseconds on the happy path.
Related https://github.com/neondatabase/neon/issues/7797
