Laurenz Albe <laurenz.albe@cybertec.at> writes: > It is not a good idea to have a mount point be the data directory.
^^^ This. ^^^
That is primarily for safety reasons: if for some reason the filesystem gets dismounted, or hasn't come on-line yet during a reboot, you do not want Postgres to be able to write on the underlying mount-point directory. There is a sobering tale in this old thread:
Now it didn't help any that they were using a start script that would automatically run initdb if it didn't see a data directory where expected. But even without that, you are in for a world of hurt if the mount drops while the server is running and the server has any ability to write on the underlying storage; it will think whatever it was able to write is safely down on disk. To prevent that, the server must not have write permissions on the mount point, which dictates making a separate data directory (with different ownership/permissions) just below the mount.
Do not bypass that ownership/permissions check. It is there for very good reasons.
