In RAC, every data block is mastered by an instance. Mastering a block simply means that master instance keeps track of the state of the block

SELECT INST_ID, OBJECT_NAME, GC_MASTERING_POLICY, CURRENT_MASTER,
  PREVIOUS_MASTER, REMASTER_CNT

FROM   GV$GCSPFMASTER_INFO G, DBA_OBJECTS O

WHERE G.DATA_OBJECT_ID = O.DATA_OBJECT_ID

ORDER BY INST_ID, REMASTER_CNT;

 

INST_ID | OBJECT_NAME       | GC_MASTERING_POLICY | CURRENT_MASTER | PREVIOUS_MASTER | REMASTER_CNT|

——————————————————————————————–

|          1|ZTLOY_MSH_ISU~0        |Affinity           |             0|              2|          11|

|          1|CRMD_ORDER_INDEX      |Affinity           |             0|              3|          11|

|          1|LOYD_MA_GENATTR~ZL  |Affinity           |             1|              0|          11|

|          1|CRMM_BUAG_H~Z03       |Affinity           |             2|              1|          11|

|          1|ZTC_LOY_MSH_BHV~Z0  |Affinity           |             0|              1|          12|

|          1|BUT020~MAD                |Affinity           |             2|              0|          12|

|          1|CRMM_BUAG_H~1          |Affinity           |             1|              0|          12|

|          1|COMD_EVHIST               |Affinity           |             0|              3|          12|

|          1|LOYD_MA_GENATTR~0   |Affinity           |             0|              1|          15|

|          1|LOYD_MA_GENATTR       |Affinity           |             0|              1|          17|

|          1|SNAP                            |Affinity           |             3|              0|          19|

|          1|BUT000~FRD                 |Affinity           |             0|              1|          23|

 

To disable DRM set the following database parameters:
_gc_policy_time=0
 and
_gc_undo_affinity=FALSE