sqlplus / as sysasm
create diskgroup?dgroup_01 external redundancy disk '/devices/disks/c*';

sqlplus / as sysasm
create diskgroup DATADG external redundancy disk '/dev/asm-diskb' ATTRIBUTE 'compatible.rdbms'='11.2','compatible.asm'='11.2';

2.给磁盘组加盘

su - grid

sqlplus / as sysasm

alter diskgroup 磁盘组的名字 ?add disk ?'/dev/rhdisk5'?rebalance power 5;

或者?alter diskgroup 磁盘组的名字 ?add disk ?'/dev/rhdisk5' ?named DISK5,add disk ?'/dev/rhdisk6' named DISK6;

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3.给磁盘组删盘

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su - grid

sqlplus / as sysasm

alter diskgroup drop disk data_01;

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4.撤销删除动作

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su - grid

sqlplus / as sysasm

alter diskgroup data undrop disk;

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5.修改asm磁盘大小

*asm中的磁盘也可以resize，需要注意：增大磁盘大小要确定对应的裸卷具有足够空间，减少空间要确保剩余的空间足以存放数据量大小，否则会报错

例：

alter diskgroup data resize disk data_01 ? size 1024m;

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6.rebalance

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ALTER DISKGROUP fra REBALANCE POWER 4 ??

alter diskgroup data drop disk DATA_0000 rebalance power 3;

power代表并行度，值越大rebalance越快，但占用资源越多

power:0~11 ? ??，?0代表不做?rebalance

11.2.0.2?版本上限为?1024

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查看rebalance进度

select operation,state,power,actual,sofar,est_work,est_minutes from v$asm_operation;

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快速rebalance方法

sqlplus / as sysasm?

startup restrict;?

alter diskgroup dgext11gasm mount restricted;?

alter diskgroup dgext11gasm rebalance power 10;?

shutdown immediate;?

startup

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7.mount/dismount?

alter diskgroup data mount/unmount

*以上操作只在当前实例挂载磁盘组，如果想每个实例都挂载，需要分别在各个实例中执行！

alter diskgroup all mount/dismount

挂载/卸载所有的磁盘组。

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8.删磁盘组（drop diskgroup）

drop diskgroup data

*需要磁盘组mount状态，对于多节点的diskgroup,只能在一个asm实例上挂载之后才能被drop，其他节点必须dismount。

另：drop diskgroup data including contents;

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9.disk online

alter diskgroup DATA online disk 'diskname';

或者：alter diskgroup DATA?online ?all;

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10.磁盘组的属性调整

alter diskgroup data set attribute 'DISK_REPAIR_TIME'='12h';

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11.文件别名操作

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加别名? ?

ALTER DISKGROUP disk_group_1 ADD ALIAS '+disk_group_1/my_dir/my_file.dbf' FOR '+disk_group_1/mydb/datafile/my_ts.342.3'; ?

改别名? ?

ALTER DISKGROUP disk_group_1 RENAME ALIAS '+disk_group_1/my_dir/my_file.dbf' TO '+disk_group_1/my_dir/my_file2.dbf'; ?

删别名? ?

ALTER DISKGROUP disk_group_1 DELETE ALIAS '+disk_group_1/my_dir/my_file.dbf'; ?

删文件? ?

ALTER DISKGROUP disk_group_1 DROP FILE '+disk_group_1/my_dir/my_file.dbf'; ?

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六、使用NORMAL冗余磁盘组的操作

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EXTERNAL means allow the underlying physical disk array do the mirroring? ?

NORMAL ? ?means ASM will create one additional copy of an extent for redundancy ? ? ?

HIGH ? ? ? ? ?means ASM will create two additional copies of an extent for redundancy ?

由于使用extent进行冗余，这种特性允许各?failure group总容量可以不一致

要改变冗余度，需要新建磁盘组?? ?

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USABALE_FILE_MB = (FREE_MB - REQUIRED_MIRROR_FREE_MB) / 2?

? ? ?1.查看failure group

select??name,total_mb,free_mb,GROUP_NUMBER,DISK_NUMBER,path,FAILGROUP,MOUNT_STATUS,HEADER_STATUS?

from v$asm_disk order by FAILGROUP

? ? ? ?

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? ? 2.创建磁盘组

sqlplus / as asmsys

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CREATE DISKGROUP data1 NORMAL REDUNDANCY ? ?

FAILGROUP data1f1 DISK ? ?

'/dev/fg11' name f1d1, ? ?

'/dev/fg12' name f1d2 ? ?

FAILGROUP data1f2 DISK ? ?

'/dev/fg21' name f2d1,? ? ?

'/dev/fg22' name f2d2 ? ?

ATTRIBUTE 'compatible.asm' = '11.2'; ? ? ? ?

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CREATE DISKGROUP data2 NORMAL REDUNDANCY ? ?

FAILGROUP data2f1 DISK ? ?

'/dev/fg13' name f3d1, ? ?

'/dev/fg14' name f3d2 ? ?

FAILGROUP data2f2 DISK ? ?

'/dev/fg23' name f4d1,? ? ?

'/dev/fg24' name f4d2 ? ?

ATTRIBUTE 'compatible.asm' = '11.2';? ?

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? 3.给磁盘组加盘

alter diskgroup DATA1 add failgourp data1f2 disk '/dev/fg21' name data1f2;

? ?*如果磁盘有盘头信息时加入会报错??

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ERROR at line 1: ? ?

ORA-15032: not all alterations performed ? ?

ORA-15033: disk '/dev/fg21' belongs to diskgroup "DATA1" ?

此时可以用force选项加盘，但注意会清掉磁盘头?

alter diskgroup data1 add failgroup data1f2 disk '/dev/fg21' name data1f2 force;

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4.disk online

alter diskgroup data1 online disk f2d1;

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5.EXTENT RAC提升读取速度

? ??在对有?failure group的读取时，默认是先读?primary copy?，由于?primary copy是交替写的，对于存储距离很远不合适，?11.1?之后提供参数调整为? ?

alter system set ASM_PREFERRED_READ_FAILURE_GROUPS='DATA.FG01'? sid='ORCL1';? ?

alter system set ASM_PREFERRED_READ_FAILURE_GROUPS='DATA.FG01'? sid='ORCL2'; ? ?

alter system set ASM_PREFERRED_READ_FAILURE_GROUPS='DATA.FG02'? sid='ORCL3'; ? ?

则每个实例优先读本地存储，适合?extend rac情况??

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