ORA-15027: active use of diskgroup "TEST_RENAME" precludes its dismount

When I try to umount the diskgroup from the ASM, it was showing the below error

I have shutdown the database using srvctl, but the database is not shutdown properly(I come to know after analyzing it) . I could see that cluster resource says that the database is down, so I didn’t  check database further. Then I found the list of active file on the DISKGROUP using “lsof” option.

Trying to umount the diskgroup

oracle +ASM1> asmcmd umount TEST_RENAME

ORA-15032: not all alterations performed

ORA-15027: active use of diskgroup "TEST_RENAME" precludes its dismount (DBD ERROR: OCIStmtExecute)

NOTE# Check the active files in ASM using the lsof. When your DISKGROUP is in active stage, we cant umount or remove the DISKGROUP. You can check by v$asm_client option but the below option is very simple.

ASMCMD [+] > lsof

DB_Name  Instance_Name  Path

….(REMOVED OTHER FILES)

BHU_B    ZS2_1          +test_rename/BHU_b/datafile/test.256.769969469