The point is that a database cannot rely on being deployed on a filesystem with proper checksums.

Ext4 uses 16-/32-bit CRCs, which is very weak for storage integrity in 2025. Many popular filesystems for databases are similarly weak. Even if they have a strong option, the strong option is not enabled by default. In real-world Linux environments, the assumption that the filesystem has weak checksums usually true.

Postgres has (IIRC) 32-bit CRCs but they are not enabled by default. That is also much weaker than you would expect from a modern database. Open source databases do not have a good track record of providing robust corruption detection generally nor the filesystems they often run on. It is a systemic problem.

ZFS doesn't support features that high-performance database kernels use and is slow, particularly on high-performance storage. Postgres does not use any of those features, so it matters less if that is your database. XFS has traditionally been the preferred filesystem for databases on Linux and Ext4 will work. Increasingly, databases don't use external filesystems at all.

I know MySQL has checksums by default, how does it compare? Is it useful or is it similarly weak?