While the Open Source cross-platform OpenZFS file system and volume manager provides advanced block-level features including checksumming, snapshotting, and replication to mitigate ransomware at the POSIX level, the evolving nature of ransomware dictates that no technology should rest on its laurels. This developer and administrator-focused talk will explore strategies for hardening OpenZFS and its supported operating systems towards a goal of total storage immutability without authorization.