by 小强哥(ouleiq)
1.关机,添加磁盘后启动机器,关闭所有节点rac及asm实例.
2.格式化磁盘,只需在一个节点上进行.
要确认在不同节点，磁盘都能够被正确识别，然后可以创建ASM磁盘组
个人建议:以下操作如只需在一个节点操作的,则最好自始至终到在一个节点上进行.
如格式化磁盘在节点1,那么接下来进行oracleasm createdisk操作最好也在节点1进行,否则可能会报错.

[root@rac01 ~]# fdisk /dev/sdg
Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p                                 
Partition number (1-4): 1
First cylinder (1-130, default 1): 1
Last cylinder or +size or +sizeM or +sizeK (1-130, default 130):
Using default value 130

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

3.在所有节点上增加 rawdevice配置
[root@rac01 ~]# vi /etc/sysconfig/rawdevices
/dev/raw/raw1 /dev/sdc1
/dev/raw/raw2 /dev/sdd1
/dev/raw/raw3 /dev/sde1
/dev/raw/raw4 /dev/sdg1  

4.以 root 用户身份在任何一个节点上创建 ASM 磁盘。
[root@rac01 ~]# /etc/init.d/oracleasm createdisk VOL5 /dev/sdg1

5.在所有节点上以oracle身份添加软连接.
rac01-> ln -sf /dev/raw/raw4 /u01/oradata/devdb/asmdisk4

6.在所有节点上改变添加的磁盘属主.
在第二个节点可能暂时看不到新加的,没关系.
[root@rac01 ~]# chown oracle:dba /dev/raw/raw[1-4]
[root@rac01 ~]# ll /dev/raw/raw*
crw-rw---- 1 oracle dba 162, 1 Aug 19 11:47 /dev/raw/raw1
crw-rw---- 1 oracle dba 162, 2 Aug 19 11:47 /dev/raw/raw2
crw-rw---- 1 oracle dba 162, 3 Aug 19 11:47 /dev/raw/raw3
crw-rw---- 1 oracle dba 162, 4 Aug 19 11:47 /dev/raw/raw4

7.在所有节点上重启rawdevices 服务.
注:在第二个节点可能会报错 Cannot locate block device '/dev/sdj1' (No such file or directory)
并无影响.
[root@rac01 ~]# service rawdevices restart
Assigning devices:
           /dev/raw/raw1 -->   /dev/sdc1
/dev/raw/raw1: bound to major 8, minor 33
           /dev/raw/raw2 -->   /dev/sdd1
/dev/raw/raw2: bound to major 8, minor 49
           /dev/raw/raw3 -->   /dev/sde1
/dev/raw/raw3: bound to major 8, minor 65
           /dev/raw/raw4 -->   /dev/sdg1
/dev/raw/raw4: bound to major 8, minor 97
done

8.在所有节点上扫描asm磁盘
[root@rac01 ~]# /etc/init.d/oracleasm scandisks
Scanning the system for Oracle ASMLib disks: [ OK ]
[root@rac01 ~]# /etc/init.d/oracleasm listdisks
VOL1
VOL2
VOL3
VOL4

9.在任意节点上添加磁盘到ASM磁盘组.

[root@rac01 ~]# su - oracle
rac01-> bash
rac01-> export ORACLE_SID=+ASM1
rac01-> sqlplus / as sysdba

SQL*Plus: Release 10.2.0.1.0 - Production on Wed Aug 19 12:35:57 2009

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Connected to an idle instance.

SQL> startup
ASM instance started

Total System Global Area   92274688 bytes
Fixed Size                  1217884 bytes
Variable Size              65890980 bytes
ASM Cache                  25165824 bytes
ASM diskgroups mounted

SQL> select group_number,name,state,total_mb from v$asm_diskgroup;

GROUP_NUMBER NAME                           STATE         TOTAL_MB
------------ ------------------------------ ----------- ----------
           1 DG1                            MOUNTED           9201
           2 RECOVERYDEST                   MOUNTED           2047

SQL> alter diskgroup DG1 ADD disk '/dev/raw/raw4';

Diskgroup altered.

SQL> select group_number,name,state,total_mb from v$asm_diskgroup;

GROUP_NUMBER NAME                           STATE         TOTAL_MB
------------ ------------------------------ ----------- ----------
           1 DG1                            MOUNTED          10220
           2 RECOVERYDEST                   MOUNTED           2047

SQL> exit