Hi, everyone. Recently, I've got a need to check the real size of an rbd image. I followed the instructions in "http://ceph.com/planet/rbd-image-real-size/";. the result is shown as follows: [xuxuehan@localhost ~]$ rbd diff xxh_pool/clone_test_img2 Offset Length Type 0 4194304 data 4194304 4190208 data 8388608 4182016 data 12582912 4194304 data 16777216 4194304 data 20971520 4194304 data 25165824 4186112 data 29360128 4190208 data 33554432 4194304 data 37748736 4190208 data 41943040 4194304 data 46137344 4186112 data 50331648 4186112 data 54525952 4194304 data 58720256 4190208 data 62914560 4194304 data However, I checked the file size of the object "rbd_data.1bfad6b8b4567.0000000000000001" which belongs to clone_test_img2, and the result is as follows: [xuxuehan@hdp2384 ~]$ du /home/ceph/software/ceph/var/lib/ceph/osd/ceph-2/current/1.154_head/rbd\\udata.1bfad6b8b4567.0000000000000001* 2020 /home/ceph/software/ceph/var/lib/ceph/osd/ceph-2/current/1.154_head/rbd\udata.1bfad6b8b4567.0000000000000001__head_A2511954__1 As shown above, the bytes changed observed in the result of "rbd diff" is about 4MB, while the real disk space usage observed by "du" is only about 2MB. Why are they so different? Please help me, thanks:-) _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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