On Thu, 3 Feb 2011, Brian Chrisman wrote: > I'm wondering whether I can get block level diff data from the > underlying rados storage to allow me to perform a kind of 'block level > incremental backup' facility. > I can't quite tell from the documentation whether this would be > supported via snapshotting (ie, can I get a map/list of blocks which > have been changed since I created a snapshot on Monday?) The OSD has this information internally. It keeps track of the unchanged overlap between each consecutive snap/version of each object (SnapSet::clone_overlap in osd/osd_types.h). I think this would just be a matter of adding an OSD operation to expose that information. See the CEPH_OSD_OP_* defines in include/rados.h, and the ceph_osd_op struct/union. sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
