The folks of EDB have run a series of benchmarks to determine how Postgres performs with different file systems under Linux. The tested file systems are ZFS, Btrfs, ext4 and XFS. They have not only tested the transactions per seconds, but also the jitter which file systems have when doing stuff.
Their overall conclusion is that Postgres with OLTP workloads performs best with ext4/XFS. ZFS is a little bit slower, but pretty consistent and has not much jitter. Btrfs on the other hand is a real stinker, performs much worse and has tons of jitter, so is not well suited for running Postgres at all.
The results can be read here: https://www.enterprisedb.com/blog/postgres-vs-file-systems-performance-comparison
Their overall conclusion is that Postgres with OLTP workloads performs best with ext4/XFS. ZFS is a little bit slower, but pretty consistent and has not much jitter. Btrfs on the other hand is a real stinker, performs much worse and has tons of jitter, so is not well suited for running Postgres at all.
The results can be read here: https://www.enterprisedb.com/blog/postgres-vs-file-systems-performance-comparison