Postgres on ZFS

I always thought that Copy-On-Write filesystems like ZFS or Btrfs were poor fit for databases because of the amount of in-place updates the database does.

This article from 2nd Quandrant actually shows that ZFS can work well with Postgres. The key seems to keep the default ZFS block size of 128k (unlike the usually recommended 8k) and use a fast disk for ZFS SLOG and cache.

The big advantage of running a database on a COW filesystem is the ability to take an atomic snapshot of the database at any moment easily.