> Of course the re-writing must be 100% safe, but that can be done with COW > quite easily.
Almost. The hard part is snapshots. If you modify a data block, you must also modify every L1 indirect block in every snapshot that points to it, and every L2 above each L1, all the way up to the uberblock. This is certainly possible, but it's tricky. But I think we'll eventually get around to doing it because the ability to remap blocks would be *so* useful -- it would enable compression of preexisting data, removing devices from a pool, automatically moving cold data to slower devices, etc. Jeff _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
