How to drop a disk from the diskgroup

SQL> select name,group_number,state,type,total_mb/1024 "Totalspace(GB)",free_mb/1024 "Freespace(GB)", (free_mb/total_mb)*100 "PCT_FREE" from v$asm_diskgroup; 
NAME                           GROUP_NUMBER STATE       TYPE   Totalspace(GB) Freespace(GB)   PCT_FREE
------------------------------ ------------ ----------- ------ -------------- ------------- ----------
PROD_RECO1                                3 MOUNTED     EXTERN           1600    1305.19922 81.5749512

SQL> Select path,disk_number,name,mount_status,header_status,os_mb/1024,total_mb/1024,free_mb/1024 from v$asm_disk where group_number=3;

PATH                  DISK_NUMBER NAME               MOUNT_S HEADER_STATU OS_MB/1024 TOTAL_MB/1024 FREE_MB/1024
--------------------- ----------- ------------------ ------- ------------ ---------- ------------- ------------
ORCL:ASM_PROD_133               0 ASM_PROD_133       CACHED  MEMBER              400           400   326.292969
ORCL:ASM_PROD_134               5 ASM_PROD_134       CACHED  MEMBER              400           400   326.273438
ORCL:ASM_PROD_135               6 ASM_PROD_135       CACHED  MEMBER              400           400     326.3125
ORCL:ASM_PROD_136               7 ASM_PROD_136       CACHED  MEMBER              400           400   326.320313

SQL> alter diskgroup PROD_RECO1 drop disk ASM_PROD_133;

Diskgroup altered.

SQL> select * from v$asm_operation;

GROUP_NUMBER OPERA STAT      POWER     ACTUAL      SOFAR   EST_WORK   EST_RATE EST_MINUTES ERROR_CODE
------------ ----- ---- ---------- ---------- ---------- ---------- ---------- ----------- --------------------------------------------
           3 REBAL RUN           1          1       1046      31956       5837           5
  
SQL> select name,group_number,state,type,total_mb/1024 "Totalspace(GB)",free_mb/1024 "Freespace(GB)", (free_mb/total_mb)*100 "PCT_FREE" from v$asm_diskgroup;

NAME                           GROUP_NUMBER STATE       TYPE   Totalspace(GB) Freespace(GB)   PCT_FREE
------------------------------ ------------ ----------- ------ -------------- ------------- ----------
PROD_RECO1                                3 MOUNTED     EXTERN           1200    901.734375 75.1445313
   
SQL> Select path,disk_number,name,mount_status,header_status,os_mb/1024,total_mb/1024,free_mb/1024 from v$asm_disk where group_number=3;

PATH                      DISK_NUMBER NAME           MOUNT_S HEADER_STATU OS_MB/1024 TOTAL_MB/1024 FREE_MB/1024
------------------------- ----------- -------------- ------- ------------ ---------- ------------- ------------
ORCL:ASM_PROD_134                   5 ASM_PROD_134   CACHED  MEMBER              400           400   301.148438
ORCL:ASM_PROD_135                   6 ASM_PROD_135   CACHED  MEMBER              400           400   301.167969
ORCL:ASM_PROD_136                   7 ASM_PROD_136   CACHED  MEMBER              400           400   301.164063


Happy Learning :)