Don't use a off the shelf database. They are overkill for this. This only needs a very single table key->value store where every transaction is only a single a

Don't use a off the shelf database. They are overkill for this. This only needs a very single table key->value store where every transaction is only a single access. I would just map it to a hash table mapped directly to the raw disk. Doesn't need transactions with a log if done right. The hash spreads out the allocation, no information leaks for the allocation. If you don't have a log there are no time stamps. Modern disks are big enough that you dont need to worry about resizing the hash table. And the random salt makes collisions unlikely enough.