ASM实例目前无论是在rac还是单实例数据库环境下都被广泛的采用，本文主要介绍Oracle 11.2.0.3环境下ASM实例的管理，主要包含以下内容：
1：ASM磁盘及磁盘组的状态查看
2：创建external 冗余磁盘组,添加，删除磁盘
3：创建normal redundancy磁盘组
4：normal redundancy下的failgroup测试
5：删除ASM磁盘组
6：其他asm实例初始化参数含义
一：查看ASM磁盘及磁盘组状态
SQL> select * from v$asm_disk;
SQL> select * from v$asm_diskgroup;
二：创建external 冗余磁盘组,添加，删除磁盘，删除磁盘的时候需要指定磁盘的name而不是path
SQL> create diskgroup FRA external redundancy disk '/dev/asm-disk4';
Diskgroup created.
SQL> alter diskgroup fra add disk '/dev/asm-disk5' rebalance power 10;
Diskgroup altered.
SQL> select name,failgroup,path from v$asm_disk;
NAME FAILGROUP PATH
-------------------- -------------------- --------------------
DATA_0000 DATA_0000 /dev/asm-disk1
DATA_0001 DATA_0001 /dev/asm-disk3
DATA_0002 DATA_0002 /dev/asm-disk2
FRA_0000 FRA_0000 /dev/asm-disk4
FRA_0001 FRA_0001 /dev/asm-disk5
/dev/asm-disk6
/dev/asm-disk7
SQL> alter diskgroup fra drop disk '/dev/asm-disk4' rebalance power 10;
alter diskgroup fra drop disk '/dev/asm-disk4' rebalance power 10
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15054: disk "/DEV/ASM-DISK4" does not exist in diskgroup "FRA"
SQL> alter diskgroup fra drop disk 'FRA_0000' rebalance power 10;
Diskgroup altered.
三：创建normal redundancy磁盘组
SQL> conn /as sysasm
Connected.
SQL> create diskgroup fra normal redundancy
failgroup fg1 disk '/dev/asm-disk4','/dev/asm-disk5'
failgroup fg2 disk '/dev/asm-disk6','/dev/asm-disk7'
attribute 'compatible.rdbms'='11.2','compatible.asm'='11.2';
Diskgroup created.
SQL> select name, total_mb,free_mb,required_mirror_free_mb,usable_file_mb from v$asm_diskgroup;
NAME TOTAL_MB FREE_MB REQUIRED_MIRROR_FREE_MB USABLE_FILE_MB
---------- ---------- ---------- ----------------------- --------------
DATA 61440 54873 0 18291
FRA 81920 81592 20480 30556
四：failgroup测试；FAILGROUP是用于将磁盘分组，以保证丢失任何一组FAILGROUP磁盘，数据还是完整的,多用于多阵列，通过ASM来完成冗余的环境！
1：查看FRA磁盘组中failgroup信息及磁盘状态
SQL> select name,path,failgroup,mount_status from v$asm_disk where group_number=2;
NAME PATH FAILGROUP MOUNT_STATUS
-------------------- -------------------- ---------- ---------------------
FRA_0003 /dev/asm-disk7 FG2 CACHED
FRA_0002 /dev/asm-disk6 FG2 CACHED
FRA_0000 /dev/asm-disk4 FG1 CACHED
FRA_0001 /dev/asm-disk5 FG1 CACHED
2：在rdbms实例中创建表空间，建表并插入数据，收集表统计信息
SQL> create tablespace test01 datafile '+FRA';
Tablespace created.
ASMCMD> pwd
+fra/db/datafile
ASMCMD> ls
TEST01.256.800622493
SQL> create table t1 tablespace test01 as select * from dba_objects;
Table created.
SQL> exec dbms_stats.gather_table_stats('SYS','T1');
PL/SQL procedure successfully completed.
SQL> select count(*) from t1;
COUNT(*)
----------
74501
3：删除udev相关规则，重启数据库实例和ASM实例，验证数据是否存在
SQL> conn /as sysasm
Connected.
SQL> alter diskgroup fra mount;
alter diskgroup fra mount
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15040: diskgroup is incomplete
ORA-15042: ASM disk "1" is missing from group number "2"
ORA-15042: ASM disk "0" is missing from group number "2"
SQL> alter diskgroup fra mount force;
Diskgroup altered.
SQL> select name,path,failgroup,mount_status from v$asm_disk;
NAME PATH FAILGROUP MOUNT_STATUS
---------- -------------------- -------------------- ---------------------
FRA_0000 FG1 MISSING
FRA_0001 FG1 MISSING
FRA_0002 /dev/asm-disk6 FG2 CACHED
FRA_0003 /dev/asm-disk7 FG2 CACHED
DATA_0000 /dev/asm-disk1 DATA_0000 CACHED
DATA_0002 /dev/asm-disk2 DATA_0002 CACHED
DATA_0001 /dev/asm-disk3 DATA_0001 CACHED
7 rows selected.
SQL> conn /as sysdba
Connected.
SQL> select count(*) from t1;
COUNT(*)
----------
74501
