**创建磁盘组：** 使用Oracle用户连接 [oracle@rac1 ~]$ sqlplus / as sysdba SQL>create diskgroup arch external redundancy disk '/dev/asm-disk5' ;  Oracle通过ASM实例管理磁盘组，要使用Gird用户连接ASM实例进行创建 [grid@rac1 ~]$ sqlplus / as sysasm SQL> create diskgroup arch external redundancy disk '/dev/asm-disk5' ; Diskgroup created. SQL> select name,state from v$asm_diskgroup; NAME STATE DATA MOUNTED OCR MOUNTED ARCH MOUNTED **卸载磁盘组：** SQL> alter diskgroup arch dismount; Diskgroup altered. 尝试卸载DATA： SQL> alter diskgroup data dismount; alter diskgroup data dismount * ERROR at line 1: ORA-15032: not all alterations performed ORA-15027: active use of diskgroup "DATA" precludes its dismount 尝试卸载OCR： SQL> alter diskgroup ocr dismount; alter diskgroup ocr dismount * ERROR at line 1: ORA-15032: not all alterations performed ORA-15027: active use of diskgroup "OCR" precludes its dismount 关闭数据库实例，尝试卸载DATA。（在两节点都关闭的情况下，才可以卸载） [grid@rac1 ~]$ srvctl stop database -d racdb; ora.racdb.db 1 OFFLINE OFFLINE Instance Shutdown 2 OFFLINE OFFLINE Instance Shutdown SQL> alter diskgroup data dismount; Diskgroup altered. OCR磁盘组无法卸载，CRSD进程以及CTSS进程使用OCR/VF磁盘组，如果关闭集群,那么ASM实例也会关闭，也就无法连接ASM实例执行磁盘组卸载命令，也无法执行asmcmd命令拉起图形化界面 。 删除磁盘组： **查看当前磁盘组状态：** SQL> select name,state from v$asm_diskgroup; NAME STATE ------------------------------ ----------- DATA MOUNTED OCR MOUNTED ARCH DISMOUNTED **删除ARCH：** SQL> drop diskgroup arch; drop diskgroup arch * ERROR at line 1: ORA-15039: diskgroup not dropped ORA-15001: diskgroup "ARCH" does not exist or is not mounted **将ARCH挂载上再次drop** SQL> alter diskgroup arch mount; Diskgroup altered. SQL> drop diskgroup arch; Diskgroup dropped. 难道dismount的磁盘组必须被mount挂载上才可以被drop删除？ 尝试一下图形化方式drop未挂载的磁盘组： 当前磁盘组信息：    使用图形化界面就可以删除dismount状态的磁盘组 **删除DATA：** SQL> drop diskgroup DATA; drop diskgroup DATA * ERROR at line 1: ORA-15039: diskgroup not dropped ORA-15053: diskgroup "DATA" contains existing files **删除OCR:** SQL> drop diskgroup OCR; drop diskgroup OCR * ERROR at line 1: ORA-15039: diskgroup not dropped ORA-15276: ASM diskgroup OCR has cluster voting files 结论： 1.挂载与使用的意义是不同的 2.当磁盘组被数据库使用时，是无法卸载和删除的，会出现下图错误：  3.ASM实例如果宕掉，那么使用ASM的数据库实例也会宕掉。 **疑问：** 为什么磁盘组dismount状态在命令行进行drop是无法删除的，还需要mount上才可以删除 使用图形化界面asmca，当磁盘组dismount状态时，可以drop进行删除。