Oracle之ASM磁盘组的重新平衡（替换磁盘过程）

由小麦苗 · 2022年3月22日

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Tags： ASM Oracle 删除磁盘替换磁盘添加磁盘磁盘组的重平衡

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简介

当磁盘组中的磁盘数发生改变时，ASM实例将对其自动进行一次重新平衡，将磁盘中的内容重新分布到现有的各个磁盘上。

用户也可以手工对磁盘组进行平衡。

参数

磁盘组的平衡能力从0-11,0表示停止平衡操作，11表示速度最快。
指定的级别越高，消耗的系统资源就越多。

ASM实例相关参数：

show parameter asm_power_limit;

1	show parameter asm_power_limit;

磁盘重新平衡能力的参数（默认参数是1，最高是11，数值越高平衡能力越强，但是消耗资源越多）

修改ASM实例参数为asm_power_limit=6：

alter system set asm_power_limit = 6 ;

1	alter system set asm_power_limit = 6 ;

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执行重平衡

执行重新平衡：

alter diskgroup FRADG rebalance;

1	alter diskgroup FRADG rebalance;

或者等待重平衡完，才返回数据给用户：

alter diskgroup FRADG rebalance wait ;

1	alter diskgroup FRADG rebalance wait ;

查询重新平衡的状态

select * from gv$asm_operation;

1	select * from gv$asm_operation;

SOFAR：就是目前为止挪动的AU数量9180
EST_WORK：估计要挪动的AU总数量71663
AU：ASM在分配空间时,以AU为单位进行,AU即Allocation units,是组成ASM disk的基本单元。此处的1个AU大小是1M，可以使用asmcmd中的lsdg直接查看。

如果select * from gv$asm_operation;有输出，则说明还在做重平衡的操作，重平衡的过程就是从其他的磁盘向新磁盘挪动数据的过程，如果数据量很大，这个时间会很长。此时，千万不能直接在后台删除磁盘。
如果没有输出，说明重新平衡已结束。

另外，若lsdg命令输出结果中，若Rebal列为Y，则代表正在执行动态平衡，需要等待动态平衡执行完成后再删除磁盘，如下：

ASMCMD> lsdg
State    Type    Rebal  Sector  Logical_Sector  Block       AU  Total_MB  Free_MB  Req_mir_free_MB  Usable_file_MB  Offline_disks  Voting_files  Name
MOUNTED  NORMAL  N         512             512   4096  4194304    153600   152676            51200           50738              0             Y  CRS/
MOUNTED  EXTERN  N         512             512   4096  1048576   6656000  3614986                0         3614986              0             N  DATA/
MOUNTED  EXTERN  Y         512             512   4096  1048576   4145152  3894686                0         3894686              0             N  FRA/
ASMCMD> lsdg
State    Type    Rebal  Sector  Logical_Sector  Block       AU  Total_MB  Free_MB  Req_mir_free_MB  Usable_file_MB  Offline_disks  Voting_files  Name
MOUNTED  NORMAL  N         512             512   4096  4194304    153600   152676            51200           50738              0             Y  CRS/
MOUNTED  EXTERN  N         512             512   4096  1048576   6656000  3614986                0         3614986              0             N  DATA/
MOUNTED  EXTERN  N         512             512   4096  1048576   2097152  1846724                0         1846724              0             N  FRA/

ASMCMD> lsdg

State Type Rebal Sector Logical_Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files Name

MOUNTED NORMAL N 512 512 4096 4194304 153600 152676 51200 50738 0 Y CRS/

MOUNTED EXTERN N 512 512 4096 1048576 6656000 3614986 0 3614986 0 N DATA/

MOUNTED EXTERN Y 512 512 4096 1048576 4145152 3894686 0 3894686 0 N FRA/

ASMCMD> lsdg

State Type Rebal Sector Logical_Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files Name

MOUNTED NORMAL N 512 512 4096 4194304 153600 152676 51200 50738 0 Y CRS/

MOUNTED EXTERN N 512 512 4096 1048576 6656000 3614986 0 3614986 0 N DATA/

MOUNTED EXTERN N 512 512 4096 1048576 2097152 1846724 0 1846724 0 N FRA/

替换磁盘的过程

1、添加新磁盘：

-- 2个节点都操作
for i in m n; do 
echo "KERNEL==\"sd*\",ENV{DEVTYPE}==\"disk\",SUBSYSTEM==\"block\",PROGRAM==\"/usr/lib/udev/scsi_id -g -u -d \$devnode\",RESULT==\"`/usr/lib/udev/scsi_id -g -u /dev/sd$i`\", RUN+=\"/bin/sh -c 'mknod /dev/asm-disk$i b  \$major \$minor; chown grid:asmadmin /dev/asm-disk$i; chmod 0660 /dev/asm-disk$i'\"" >> /etc/udev/rules.d/99-oracle-asmdevices.rules
done

/sbin/udevadm trigger --type=devices --action=change
/sbin/udevadm control --reload
ll /dev/asm*

-- 1个节点操作
alter diskgroup fra add disk '/dev/asm-diskm';
alter diskgroup fra add disk '/dev/asm-diskn';

-- 查询
col name format a10
set line 9999
col path format a25
select GROUP_NUMBER,path,name,disk_number,total_mb,free_mb,CREATE_DATE,MOUNT_STATUS,MOUNT_DATE from v$asm_disk order by GROUP_NUMBER desc,disk_number;
select name,state,free_mb,required_mirror_free_mb,usable_file_mb from v$asm_diskgroup;

-- 2个节点都操作

for i in m n; do

echo "KERNEL==\"sd*\",ENV{DEVTYPE}==\"disk\",SUBSYSTEM==\"block\",PROGRAM==\"/usr/lib/udev/scsi_id -g -u -d \$devnode\",RESULT==\"`/usr/lib/udev/scsi_id -g -u /dev/sd$i`\", RUN+=\"/bin/sh -c 'mknod /dev/asm-disk$i b \$major \$minor; chown grid:asmadmin /dev/asm-disk$i; chmod 0660 /dev/asm-disk$i'\"" >> /etc/udev/rules.d/99-oracle-asmdevices.rules

done

/sbin/udevadm trigger --type=devices --action=change

/sbin/udevadm control --reload

ll /dev/asm*

-- 1个节点操作

alter diskgroup fra add disk '/dev/asm-diskm';

alter diskgroup fra add disk '/dev/asm-diskn';

-- 查询

col name format a10

set line 9999

col path format a25

select GROUP_NUMBER,path,name,disk_number,total_mb,free_mb,CREATE_DATE,MOUNT_STATUS,MOUNT_DATE from v$asm_disk order by GROUP_NUMBER desc,disk_number;

select name,state,free_mb,required_mirror_free_mb,usable_file_mb from v$asm_diskgroup;

2、删除旧磁盘

alter diskgroup fra drop disk FRA_0000;
alter diskgroup fra drop disk FRA_0001;

-- 也可以删除磁盘的时候做动态平衡
alter diskgroup DATA drop disk 'VOL2' rebalance power 10;

-- 此时查询，被删除的磁盘仍然属于FRA磁盘组，切记不能在后台删除磁盘
col name format a10
set line 9999
col path format a25
select GROUP_NUMBER,path,name,disk_number,total_mb,free_mb,CREATE_DATE,MOUNT_STATUS,MOUNT_DATE from v$asm_disk order by GROUP_NUMBER desc,disk_number;
select name,state,free_mb,required_mirror_free_mb,usable_file_mb from v$asm_diskgroup;

GROUP_NUMBER PATH                      NAME       DISK_NUMBER   TOTAL_MB    FREE_MB CREATE_DA MOUNT_S MOUNT_DAT
------------ ------------------------- ---------- ----------- ---------- ---------- --------- ------- ---------
           3 /dev/asm-diskh            FRA_0000             0    1024000     908943 09-NOV-21 CACHED  09-MAR-22
           3 /dev/asm-diskj            FRA_0001             1    1024000     906347 09-NOV-21 CACHED  09-MAR-22
           3 /dev/asm-diskl            FRA_0002             2    2097152    2079396 22-MAR-22 CACHED  22-MAR-22
           2 /dev/asm-diskg            DATA_0000            0    1024000     555995 09-NOV-21 CACHED  09-MAR-22
           2 /dev/asm-diskd            DATA_0001            1    1024000     555972 09-NOV-21 CACHED  09-MAR-22
           2 /dev/asm-diske            DATA_0002            2    1024000     556001 09-NOV-21 CACHED  09-MAR-22
           2 /dev/asm-diskf            DATA_0003            3    1024000     555971 09-NOV-21 CACHED  09-MAR-22
           2 /dev/asm-diski            DATA_0004            4    1536000     835063 20-NOV-21 CACHED  09-MAR-22
           2 /dev/asm-diskk            DATA_0005            5    1024000     555984 20-NOV-21 CACHED  09-MAR-22
           1 /dev/asm-diska            CRS_0000             0      51200      50884 09-NOV-21 CACHED  09-MAR-22
           1 /dev/asm-diskc            CRS_0001             1      51200      50900 09-NOV-21 CACHED  09-MAR-22
           1 /dev/asm-diskb            CRS_0002             2      51200      50892 09-NOV-21 CACHED  09-MAR-22

12 rows selected.

alter diskgroup fra drop disk FRA_0000;

alter diskgroup fra drop disk FRA_0001;

-- 也可以删除磁盘的时候做动态平衡

alter diskgroup DATA drop disk 'VOL2' rebalance power 10;

-- 此时查询，被删除的磁盘仍然属于FRA磁盘组，切记不能在后台删除磁盘

col name format a10

set line 9999

col path format a25

select GROUP_NUMBER,path,name,disk_number,total_mb,free_mb,CREATE_DATE,MOUNT_STATUS,MOUNT_DATE from v$asm_disk order by GROUP_NUMBER desc,disk_number;

select name,state,free_mb,required_mirror_free_mb,usable_file_mb from v$asm_diskgroup;

GROUP_NUMBER PATH NAME DISK_NUMBER TOTAL_MB FREE_MB CREATE_DA MOUNT_S MOUNT_DAT

------------ ------------------------- ---------- ----------- ---------- ---------- --------- ------- ---------

3 /dev/asm-diskh FRA_0000 0 1024000 908943 09-NOV-21 CACHED 09-MAR-22

3 /dev/asm-diskj FRA_0001 1 1024000 906347 09-NOV-21 CACHED 09-MAR-22

3 /dev/asm-diskl FRA_0002 2 2097152 2079396 22-MAR-22 CACHED 22-MAR-22

2 /dev/asm-diskg DATA_0000 0 1024000 555995 09-NOV-21 CACHED 09-MAR-22

2 /dev/asm-diskd DATA_0001 1 1024000 555972 09-NOV-21 CACHED 09-MAR-22

2 /dev/asm-diske DATA_0002 2 1024000 556001 09-NOV-21 CACHED 09-MAR-22

2 /dev/asm-diskf DATA_0003 3 1024000 555971 09-NOV-21 CACHED 09-MAR-22

2 /dev/asm-diski DATA_0004 4 1536000 835063 20-NOV-21 CACHED 09-MAR-22

2 /dev/asm-diskk DATA_0005 5 1024000 555984 20-NOV-21 CACHED 09-MAR-22

1 /dev/asm-diska CRS_0000 0 51200 50884 09-NOV-21 CACHED 09-MAR-22

1 /dev/asm-diskc CRS_0001 1 51200 50900 09-NOV-21 CACHED 09-MAR-22

1 /dev/asm-diskb CRS_0002 2 51200 50892 09-NOV-21 CACHED 09-MAR-22

12 rows selected.

注意，此处，删除磁盘时只能使用磁盘的名称，不能使用路径否则会报错ORA-15054，disk "ORCL:VOL2" does not exist in diskgroup "DATA"。

3、做动态平衡

alter system set asm_power_limit = 6 sid='*' ;
alter diskgroup FRA rebalance wait ;
select * from gv$asm_operation;

alter system set asm_power_limit = 6 sid='*' ;

alter diskgroup FRA rebalance wait ;

select * from gv$asm_operation;

等待完成，等待视图gv$asm_operation的结果为空。

4、后台删除旧磁盘。

-- 此时查询，被删除的磁盘不属于任何磁盘组
col name format a10
set line 9999
col path format a25
select GROUP_NUMBER,path,name,disk_number,total_mb,free_mb,CREATE_DATE,MOUNT_STATUS,MOUNT_DATE from v$asm_disk order by GROUP_NUMBER desc,disk_number;
select name,state,free_mb,required_mirror_free_mb,usable_file_mb from v$asm_diskgroup;

SQL> select GROUP_NUMBER,path,name,disk_number,total_mb,free_mb,CREATE_DATE,MOUNT_STATUS,MOUNT_DATE from v$asm_disk order by GROUP_NUMBER desc,disk_number;

GROUP_NUMBER PATH                      NAME       DISK_NUMBER   TOTAL_MB    FREE_MB CREATE_DA MOUNT_S MOUNT_DAT
------------ ------------------------- ---------- ----------- ---------- ---------- --------- ------- ---------
           3 /dev/asm-diskl            FRA_0002             2    2097152    1846724 22-MAR-22 CACHED  22-MAR-22
           2 /dev/asm-diskg            DATA_0000            0    1024000     555995 09-NOV-21 CACHED  09-MAR-22
           2 /dev/asm-diskd            DATA_0001            1    1024000     555972 09-NOV-21 CACHED  09-MAR-22
           2 /dev/asm-diske            DATA_0002            2    1024000     556001 09-NOV-21 CACHED  09-MAR-22
           2 /dev/asm-diskf            DATA_0003            3    1024000     555971 09-NOV-21 CACHED  09-MAR-22
           2 /dev/asm-diski            DATA_0004            4    1536000     835063 20-NOV-21 CACHED  09-MAR-22
           2 /dev/asm-diskk            DATA_0005            5    1024000     555984 20-NOV-21 CACHED  09-MAR-22
           1 /dev/asm-diska            CRS_0000             0      51200      50884 09-NOV-21 CACHED  09-MAR-22
           1 /dev/asm-diskc            CRS_0001             1      51200      50900 09-NOV-21 CACHED  09-MAR-22
           1 /dev/asm-diskb            CRS_0002             2      51200      50892 09-NOV-21 CACHED  09-MAR-22
           0 /dev/asm-diskj                                 0          0          0 09-NOV-21 CLOSED  09-MAR-22
           0 /dev/asm-diskh                                 1          0          0 09-NOV-21 CLOSED  09-MAR-22

12 rows selected.

-- 此时查询，被删除的磁盘不属于任何磁盘组

col name format a10

set line 9999

col path format a25

select GROUP_NUMBER,path,name,disk_number,total_mb,free_mb,CREATE_DATE,MOUNT_STATUS,MOUNT_DATE from v$asm_disk order by GROUP_NUMBER desc,disk_number;

select name,state,free_mb,required_mirror_free_mb,usable_file_mb from v$asm_diskgroup;

SQL> select GROUP_NUMBER,path,name,disk_number,total_mb,free_mb,CREATE_DATE,MOUNT_STATUS,MOUNT_DATE from v$asm_disk order by GROUP_NUMBER desc,disk_number;

GROUP_NUMBER PATH NAME DISK_NUMBER TOTAL_MB FREE_MB CREATE_DA MOUNT_S MOUNT_DAT

------------ ------------------------- ---------- ----------- ---------- ---------- --------- ------- ---------

3 /dev/asm-diskl FRA_0002 2 2097152 1846724 22-MAR-22 CACHED 22-MAR-22