ORA-15027: Active Use Of Diskgroup Precludes Its Dismount

Problem :

While dismounting a diskgroup, got the below error:

Solution :

There might be some running databases using that diskgroup. check v$asm_client, for active connections to that diskgroup

set pagesize 299
set lines 2999
col instance_name for a21
select a.instance_name,a.db_name,a.status from v$asm_client a, v$asm_diskgroup b
where a.group_number=b.group_number and b.name='NEWTST';

INSTANCE_NAME DB_NAME STATUS
--------------------- -------- ------------
TESTDB1 TESTDB CONNECTED
+ASM1 +ASM CONNECTED

The database TESTDB is running and using this diskgroup, shutdown the database and try to dismount.

srvctl stop database -d TESTDB

SQL> alter diskgroup NEWTST dismount;

Diskgroup altered.