I've been thinking about this, and I wanted to hear your thoughts on pros, cons, use-cases, anything you feel is relevant, etc.
I found this repo: https://github.com/ambv/bitrot . Its single feature is to recursively hash every file in a directory tree and store the hashes in a SQLite DB. If both the mtime and the file have changed, update the hash, otherwise alert the user that the file has changed (bit rot or other problems). It got me thinking: what does Snapraid bring to the table that this doesn't?
AFAIK, Snapraid can recreate a failed drive from the parity information, which a DIY method couldn't (without recreating Snapraid, at which point, just use Snapraid).
But, Snapraid requires a dedicated parity drive, thus using a drive you could fill with more data (of course the hash DB would take up space too). Also, you could backup the hash DB from a DIY method.
Going DIY would mean if a file does bit rot, you would have to go to a backup to get a non-corrupt copy.
The repo I linked hasn't been updated in 2 years, and SHA1 may be overkill (wouldn't MD5 suffice?). So I'm asking in a general sense, not specifically this exact repo.
It also depends on the data in question: a photo collection is much more static than a database server. Since Snapraid only suits more static data, let's focus on that use case