On Fri, Mar 9, 2018 at 11:05 AM, <[email protected]> wrote: > Hi, > > I am looking for information regarding rbd's --whole-object option > According to the doc: > --whole-object > Specifies that the diff should be limited to the extents of a full > object instead of showing intra-object deltas. When the object map > feature is enabled on an image, limiting the diff to the object extents > will dramatically improve performance since the differences can be > computed by examining the in-memory object map instead of querying RADOS > for each object within the image. > > Is there any drawback ?
The only drawback is that your export-diff might be larger. For example, changing 1 bytes within a 4MB backing object block will result in a 4MB export instead of a 1 byte export. > If I use this option when object-map is enabled, is this only benefical ? > What does it do if this feature is disabled ? It behaves the same way -- it will export the full object if at least one byte has changed. > Why is `whole-object` an option, and not the default behavior ? ... because it can result in larger export-diffs. > Regards, > _______________________________________________ > ceph-users mailing list > [email protected] > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com -- Jason _______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
