Hi, All When I type 'ceph health' to get the status of cluster, it will show some information. Would you please to explain the term? Ex: HEALTH_WARN 3/54 degraded (5.556%) What does "degraded" mean ? Is it a serious error and how to fix it ? Ex: HEALTH_WARN 264 pgs degraded, 6/60 degraded (10.000%); 3/27 unfound (11.111%) What does "unfound" mean? Could we recover the data? Would it cause the whole data in rbd image corrupted and never access ? When I type 'ceph pg dump', it would show like this. Would you please explain what is "hb in" and "hb out" ? osdstat kbused kbavail kb hb in hb out 0 17300872 1884175720 1906311168 [6,7,8,9,10,11] [6,7,8,9,10,11] 1 16661664 1884808728 1906311168 [6,7,8,9,10,11] [6,7,8,9,10,11] 2 15695664 1886027584 1906311168 [6,7,8,9,10,11] [6,7,8,9,10,11] 3 16463440 1885005328 1906311168 [6,7,8,9,10,11] [6,7,8,9,10,11] 4 14101016 1888130760 1906311168 [6,7,8,9,10,11] [6,7,8,9,10,11] 5 14015804 1888215124 1906311168 [6,7,8,9,10,11] [6,7,8,9,10,11] 6 19312280 1881660776 1906311168 [0,1,2,3,4,5] [0,1,2,3,4,5] 7 14451992 1887521200 1906311168 [0,1,2,3,4,5] [0,1,2,3,4,5] 8 16336028 1885393468 1906311168 [0,1,2,3,4,5] [0,1,2,3,4,5] 9 16697868 1884773940 1906311168 [0,1,2,3,4,5] [0,1,2,3,4,5] 10 13530456 1888695776 1906311168 [0,1,2,3,4,5] [0,1,2,3,4,5] 11 13921908 1888307364 1906311168 [0,1,2,3,4,5] [0,1,2,3,4,5] sum 188488992 22632715768 22875734016 And from the latest document, I know we can do the cluster snapshot by " ceph osd cluster_snap <name>" Is that means we can rollback the data from the snapshot? Do you have any related document to show how to operate it? Thanks a lot! -- 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