Copy on write for everything

Snapshots

Another implementation of raid. Not at device layer. Just make sure we have copies of data.

File compression. Check first time if file can be compressed.

Trim support.

Copy on write fragmentation is an issue.

Per file controls.

Defragmentation occurs quickly.

Scrub at least once a month. For raid1 and raid10. Fix blocks with errors. For infrequently read blocks.

Checksums for everything.