mknod /etc/udev/devices/rlvasmdisk3 c 162 3 mknod /etc/udev/devices/rlvasmdisk4 c 162 4 mknod /etc/udev/devices/rlvasmdisk5 c 162 5 mknod /etc/udev/devices/rlvasmdisk6 c 162 6 mknod /etc/udev/devices/rlvasmdisk7 c 162 7 mknod /etc/udev/devices/rlvasmdisk8 c 162 8 chown -R oracle:dba /etc/udev/devices/rlvasm* start_udev raw /dev/rlvasmdisk1 /dev/vg_asmgp1/lvasmdisk1 raw /dev/rlvasmdisk2 /dev/vg_asmgp1/lvasmdisk2 raw /dev/rlvasmdisk3 /dev/vg_asmgp1/lvasmdisk3 raw /dev/rlvasmdisk4 /dev/vg_asmgp1/lvasmdisk4 raw /dev/rlvasmdisk5 /dev/vg_asmgp1/lvasmdisk5 raw /dev/rlvasmdisk6 /dev/vg_asmgp1/lvasmdisk6 raw /dev/rlvasmdisk7 /dev/vg_asmgp1/lvasmdisk7 raw /dev/rlvasmdisk8 /dev/vg_asmgp1/lvasmdisk8 - 6 -
SQL> show parameter asm NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ asm_diskgroups string asm_diskstring string /dev/rlvasm* asm_power_limit integer 1 CREATE DISKGROUP DSKGRP1 NORMAL REDUNDANCY FAILGROUP controller1 DISK '/dev/rlvasmdisk1', '/dev/rlvasmdisk2' FAILGROUP controller2 DISK '/dev/rlvasmdisk3', '/dev/rlvasmdisk4'; SQL> show parameter asm NAME TYPE VALUE ------------------------------------ ----------- ------------------------------
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asm_diskgroups string DSKGRP1 asm_diskstring string /dev/rlvasm* asm_power_limit integer 1 在这里创建了一个磁盘组DSKGRP1，设置了对应的磁盘镜像。在组controller1上写数据的同时，相同的数据被复制到组controller2上。保证数据有冗余备份。避免了数据丢失。
[oracle@server bdump]$ ps -ef|grep asm oracle 4235 1 0 20:49 ? 00:00:00 asm_pmon_+ASM oracle 4237 1 0 20:49 ? 00:00:00 asm_psp0_+ASM oracle 4239 1 0 20:49 ? 00:00:00 asm_mman_+ASM oracle 4241 1 0 20:49 ? 00:00:00 asm_dbw0_+ASM oracle 4243 1 0 20:49 ? 00:00:00 asm_lgwr_+ASM oracle 4245 1 0 20:49 ? 00:00:00 asm_ckpt_+ASM oracle 4247 1 0 20:49 ? 00:00:00 asm_smon_+ASM oracle 4249 1 0 20:49 ? 00:00:00 asm_rbal_+ASM oracle 4251 1 0 20:49 ? 00:00:00 asm_gmon_+ASM 4.3 修改磁盘组
在工作过程中，需要给磁盘组添加或删除磁盘，在添加或删除过程中，ASM会重新自动平衡数据的分布。在整个平衡过程中，可以通过查看V$ASM_OPERATION视图。
alter system set asm_diskstring='/dev/rlvasm*' 4.3.1 给一个磁盘组添加设备
SQL> ALTER DISKGROUP DSKGRP1 ADD FAILGROUP controller1 DISK '/dev/rlvasmdisk5' NAME asmdisk5; SQL> ALTER DISKGROUP DSKGRP1 ADD FAILGROUP controller2 DISK '/dev/rlvasmdisk6' NAME asmdisk6; - 8 -
4.3.2 删除设备
当一个磁盘设备被删除的时候，磁盘组数据会重新分布，将被删除磁盘上的数据从新分布到现存的磁盘设备上。如果现有的磁盘设备空间不足，删除操作会失败。所以在删除磁盘设备前要先确定磁盘空间足够使用。
SQL> select name, type, total_mb, free_mb, required_mirror_free_mb,usable_file_mb from v$asm_diskgroup; NAME TYPE TOTAL_MB FREE_MB REQUIRED_MIRROR_FREE_MB USABLE_FILE_MB ------------------------------ ------ ---------- ---------- ----------------------- DSKGRP1 NORMAL 1200 1090 200 445 删除一个sdd1,sdd2的设备
SQL> ALTER DISKGROUP DSKGRP1 DROP DISK asmdisk5; SQL> select name, type, total_mb, free_mb, required_mirror_free_mb,usable_file_mb from v$asm_diskgroup; NAME TYPE TOTAL_MB FREE_MB REQUIRED_MIRROR_FREE_MB USABLE_FILE_MB ------------------------------ ------ ---------- ---------- ----------------------- DSKGRP1 NORMAL 1000 892 200 346 SQL> ALTER DISKGROUP DSKGRP1 DROP DISK asmdisk6; SQL> select name, type, total_mb, free_mb, required_mirror_free_mb,usable_file_mb from v$asm_diskgroup; NAME TYPE TOTAL_MB FREE_MB REQUIRED_MIRROR_FREE_MB USABLE_FILE_MB ------------------------------ ------ ---------- ---------- ----------------------- DSKGRP1 NORMAL 800 694 200 247
4.3.3 修改磁盘空间大小
ALTER DISKGROUP DSKGRP1 RESIZE DISKS IN FAILGROUP controller1 SIZE 200M; 在操作系统扩容后，数据库不能直接认到磁盘发生了变化，需要手工调整磁盘的大小。
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4.3.4 取消磁盘删除
ALTER DISKGROUP DSKGRP1 UNDROP DISKS;
4.3.5 手工重新分布数据
asm_power_limit参数可以设置为0-11，如果设置为0，那么ASM自动重新分布数据功能会被关闭。
SQL> alter system set asm_power_limit = 0; SQL> show parameter asm_power_limit NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ asm_power_limit integer 0 手工分布数据
SQL> ALTER DISKGROUP DSKGRP1 REBALANCE POWER 2 WAIT; 查看数据分布需要多长时间
SQL>select operation,est_minutes from v$asm_operation;
4.3.6 手工mount,dismount磁盘组
SQL> ALTER DISKGROUP DSKGRP1 DISMOUNT; SQL> ALTER DISKGROUP DSKGRP1 MOUNT;
4.4 检查磁盘设备一致性
ALTER DISKGROUP DSKGRP1 CHECK ALL; ALTER DISKGROUP DSKGRP1 CHECK ALL repair;(删除完FAILGROUP磁盘组后，需要手工CHECK所有的磁盘信息)
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