Gotta preach for the cult of ZFS. It’s check summing, copy on write, and zraid features are all exactly what you want for data resilience. Plus you get transparent compression, and snapshots that can provide a bit of a stop-gap for your lack of backups.

It will normally soak up any and all memory for buffers and caches, but is meant to quickly free up when it’s needed by an app. Linux already does this on any filesystem with its page cache.

Oh and mounting a ZFS dataset on a new machine is super quick and easy, it stores it’s config on the drives themselves, so you can plug them into a new box and zpool import -af and boom it’s mounted and ready to go.