#postgres + #databases

It is possible to use an NFS file system for storing the PostgreSQL data directory. PostgreSQL does nothing special for NFS file systems, meaning it assumes NFS behaves exactly like locally-connected drives. PostgreSQL does not use any functionality that is known to have nonstandard behavior on NFS, such as file locking.

The only firm requirement for using NFS with PostgreSQL is that the file system is mounted using the hard option. With the hard option, processes can “hang” indefinitely if there are network problems, so this configuration will require a careful monitoring setup.

It is not necessary to use the sync mount option. The behavior of the async option is sufficient, since PostgreSQL issues fsync calls at appropriate times to flush the write caches. (This is analogous to how it works on a local file system.) However, it is strongly recommended to use the sync export option on the NFS server on systems where it exists (mainly Linux). Otherwise, an fsync or equivalent on the NFS client is not actually guaranteed to reach permanent storage on the server, which could cause corruption similar to running with the parameter fsync off.

After watching this amazing talk, I realized that as long as we can guarantee that WAL (Write-Ahead Logs) buffers are written to the network storage, the database should be able to recover from the errors in case of a failure. Armed with this knowledge, I made an attempt on storing Postgres data on an NFS share.