NAS OS - OpenZFS code-walk - FreeNAS ZFS - Ubuntu ZFS - Deduplication and Compression
NAS OS - OpenZFS code-walk - FreeNAS ZFS - Ubuntu ZFS - Deduplication and Compression

Refer:
OpenZFS Wiki ↗
openzfs.org ↗
OpenZFS on Linux and FreeBSD github ↗
TrueNAS (formerly FreeNAS) ↗