Well, it was just an example, it wouldn't really work either way, would be too slow for HDDs and would still require handling of all the disk reliability and pe

Well, it was just an example, it wouldn't really work either way, would be too slow for HDDs and would still require handling of all the disk reliability and performance issues. But if I were to do it today and store metadata in an SQLite database I would use a single database for all the shards and use its VFS API where I would add I/O scheduling, remapping of blocks with redundancy into different blocks and automatic recovery, marking of bad and slow blocks, and maybe even scrubbing. Looks like half of the storage engine already and it would still be somewhat slow.