Ceph » RADOS

I reproduced this by creating an inconsistent pg and then causing it to split.

pool of size 2 with 1 pg and I created an inconsistency in one object (it had 2 scrub errors, size and data_digest_mismatch)

After pg_num/pgp_num to 8, there was only 1 resulting pg on a single replica with num_scrub_errors and the value was 1.

PG_STAT OBJECTS MISSING_ON_PRIMARY DEGRADED MISPLACED UNFOUND BYTES LOG DISK_LOG STATE        STATE_STAMP                VERSION REPORTED UP    UP_PRIMARY ACTING ACTING_PRIMARY LAST_SCRUB SCRUB_STAMP                LAST_DEEP_SCRUB DEEP_SCRUB_STAMP           SNAPTRIMQ_LEN
1.7          12                  0        0         0       0 20048 101      101 active+clean 2018-03-21 19:46:17.366706  11'101   20:169 [1,2]          1  [1,2]              1     11'101 2018-03-21 19:43:22.172793          11'101 2018-03-21 19:43:22.172793             0
1.6          12                  0        0         0       0 20048 101      101 active+clean 2018-03-21 19:46:15.176818  11'101   19:146 [1,0]          1  [1,0]              1     11'101 2018-03-21 19:43:22.172793          11'101 2018-03-21 19:43:22.172793             0
1.5          13                  0        0         0       0 20048 101      101 active+clean 2018-03-21 19:46:18.414012  11'101    20:54 [2,0]          2  [2,0]              2     11'101 2018-03-21 19:43:22.172793          11'101 2018-03-21 19:43:22.172793             0
1.4          13                  0        0         0       0 20049 101      101 active+clean 2018-03-21 19:46:15.181264  11'101   19:146 [1,0]          1  [1,0]              1     11'101 2018-03-21 19:43:22.172793          11'101 2018-03-21 19:43:22.172793             0
1.3          13                  0        0         0       0 20049 101      101 active+clean 2018-03-21 19:46:18.724337  11'101   20:173 [1,2]          1  [1,2]              1     11'101 2018-03-21 19:43:22.172793          11'101 2018-03-21 19:43:22.172793             0
1.2          13                  0        0         0       0 20049 101      101 active+clean 2018-03-21 19:46:16.187580  11'101   20:136 [0,1]          0  [0,1]              0     11'101 2018-03-21 19:43:22.172793          11'101 2018-03-21 19:43:22.172793             0
1.1          13                  0        0         0       0 20049 101      101 active+clean 2018-03-21 19:46:19.378158  11'101    20:30 [2,0]          2  [2,0]              2     11'101 2018-03-21 19:43:22.172793          11'101 2018-03-21 19:43:22.172793             0
1.0          12                  0        0         0       0 20048 101      101 active+clean 2018-03-21 19:46:15.174846  11'101   19:147 [1,0]          1  [1,0]              1     11'101 2018-03-21 19:43:22.172793          11'101 2018-03-21 19:43:22.172793             0

Interestingly, all the primaries have num_scrub_errors == 0, but a single post-split pg replica has a non-zero value.

1.0
                "num_scrub_errors": 0,
                    "num_scrub_errors": 0,
1.1
                "num_scrub_errors": 0,
                    "num_scrub_errors": 0,
1.2
                "num_scrub_errors": 0,
                    "num_scrub_errors": 1,
1.3
                "num_scrub_errors": 0,
                    "num_scrub_errors": 0,
1.4
                "num_scrub_errors": 0,
                    "num_scrub_errors": 0,
1.5
                "num_scrub_errors": 0,
                    "num_scrub_errors": 0,
1.6
                "num_scrub_errors": 0,
                    "num_scrub_errors": 0,
1.7
                "num_scrub_errors": 0,
                    "num_scrub_errors": 0,

merged https://github.com/ceph/ceph/pull/21194