This way PEX is still enabled and can provide at least some form of permissions resolution. What needs to be decided is what to do when the fallback backend is used:

1. Lock down the server and grant no permissions to anybody
2. Kick everyone on join
3. Send a message to anyone who joins giving information about the error (while taking one of the above actions)

Pex can use two different data stores at the same time yet e.g. For migration of permissions storage.
Wouldn't it be nice to have a configuration switch to enable fallback from database to file based data store if the DB connection breaks. This would need to have a valid and mostly up to date replication of the permissions.yml extracted from the pex DB schema in a regular base or another external tool would be needed to realize those extraction via cronjob for example.
If this seems to be too complex is there a chance to get native MySQL reconnection within pex realized ?