The same time the lost data was piling up, people were reporting floods of “unable to delete piece” log entries. (and from the stack track in that top example I see “*(pieceExpirationDB).GetExpired:71\n\tstorj.io/storj/storagenode/pieces” which sounds like it could be the TTL cleanup logic.
If anything was wrong with the TTL DB entries (like a path/piece was off by one character or something)… could the cleanup logic just fail to delete the piece… but delete the DB entry anyways… and thus forget about the TTL piece in the blobs folder?
Even if it’s fixed now… if it was b0rked in 105 or 108 or something then a lot of lost TTL data would still be hanging around.