>If I have a directory with a bazillion files in it (or, let's say, a >directory subtree full of raw camera images, about 15MB each, totalling >say 50GB) on a ZFS filesystem, and take daily snapshots of it (without >altering it), the snapshots use almost no extra space, I know. > >If I now rename that directory, and take another snapshot, what happens? >Do I get two copies of the unchanged data now, or does everything still >reference the same original data (file content)? Seems like the new >directory tree contains the "same old files", same inodes and so forth, so >it shouldn't be duplicating the data as I understand it; is that correct? > >This would, obviously, be fairly easy to test; and, if I removed the >snapshots afterward, wouldn't take space permanently (have to make sure >that the scheduler doesn't do one of my permanent snapshots during the >test). But I'm interested in the theoretical answer in any case.
snapshots never take additional space until it starts to reference deleted data. If the directory is renamed then the parent directory is changed and the directory's inode but the rest of the data is not modified and has no effect on the amount of data stored. Casper _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
