> The 45 byte score is the checksum of the top of the tree, isn't that > right?
Yes. Plus an optional label. > ZFS snapshots and clones save a lot of space, but the > 'content-hash == address' trick means you could potentially save > much more. Especially if you carry around large files (disk images, databases) that change. > Though I'm still not sure how well it scales up - > Bigger working set means you need longer (more expensive) hashes > to avoid a collision, and even then its not guaranteed. > When i last looked they were still using SHA-160 > and I ran away screaming at that point :) You need 2^80 blocks for a 50%+ probability that a pair will have the same SHA-160 hash (by the birthday paradox). Crypto attacks are not relevant. For my personal use I am willing to live with these odds until my backups cross 2^40 distinct blocks (greater than 8 Petabytes)! _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
