ASM變遷以及總結（10G--＞19C）
10G:
從10G開始，出現GRID網格工具，ASM不支持存放OCR和Voting Disks，需要使用OCFS或者OCFS2。
Table 3-1 Supported Storage Options?for Oracle Clusterware, Database, and Recovery Files
Automatic Storage Management
|
No
|
No
|
Yes
|
Yes
|
|
OCFS
|
Yes
|
No
|
Yes
|
Yes
|
|
OCFS2
|
Yes
|
Yes
|
Yes
|
Yes
|
|
GPFS (for Linux on POWER)
|
Yes
|
Yes
|
Yes
|
Yes
|
|
Local storage
|
No
|
Yes
|
No
|
No
|
|
NFS file system
Note:?Requires a certified NAS device
|
Yes
|
Yes
|
Yes
|
Yes
|
|
Shared raw partitions
|
Yes
|
No
|
Yes
|
No
|
|
Block devices?(IBM zSeries based systems only)
|
Yes
|
Yes
|
Yes
|
No
|
ASM冗余方式：
冗余方式有3種：External、Normal、High。
僅支持數據文件和恢復文件存放，需要磁盤數量對應冗余為1、2、3。
Use the following table to determine the minimum number of disks and the minimum disk space requirements for installing the starter database:
11G:
從11G開始，ASM支持OCR和Voting Disk Files存放，OCFS淘汰，開始大量使用ASM。
Table 3-2 Supported Storage Options?for Oracle Clusterware and Oracle RAC
Oracle Automatic Storage Management (Oracle ASM)
Note: Loopback devices are not supported for use with Oracle ASM
|
Yes
|
No
|
No
|
Yes
|
Yes
|
|
Oracle Automatic Storage Management Cluster File System (Oracle ACFS)
|
No
|
No
|
Yes
|
No
|
No
|
|
Local file system
|
No
|
Yes
|
Yes
|
No
|
No
|
|
NFS file system on a certified NAS filer
Note:?Direct NFS Client does not support Oracle Clusterware files.
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
|
Shared disk partitions (block devices or raw devices)
|
Not supported by OUI or ASMCA, but supported by the software. They can be added or removed after installation.
|
No
|
No
|
Not supported by OUI or ASMCA, but supported by the software. They can be added or removed after installation.
|
No
|
ASM冗余方式：
冗余方式有3種：External、Normal、High。
OCR和Voting Disk需要磁盤數量對應冗余：1、3、5。
Table 3-5 Total Oracle Clusterware Storage Space Required by Redundancy Type
External
|
1
|
300 MB
|
300 MB
|
600 MB
|
|
Normal
|
3
|
600 MB
|
900 MB
|
1.5 GBFoot?1
|
|
High
|
5
|
900 MB
|
1.5 GB
|
2.4 GB
|
數據文件和恢復文件存放，需要磁盤數量對應冗余為1、2、3。
Table 3-6 Total Oracle Database Storage Space Required by Redundancy Type
External
|
1
|
1.5 GB
|
3 GB
|
4.5 GB
|
|
Normal
|
2
|
3 GB
|
6 GB
|
9 GB
|
|
High
|
3
|
4.5 GB
|
9 GB
|
13.5 GB
|
19C:
從19C開始，重新支持OCFS2（僅支持存放數據文件和恢復文件）。
19C開始支持CDB和PDB。
Table 7-1 Supported Storage Options for Oracle Grid Infrastructure
Oracle Automatic Storage Management (Oracle ASM)
Note: Loopback devices are not supported for use with Oracle ASM
|
Yes
|
No
|
No
|
Yes
|
Yes
|
| Oracle Automatic Storage Management Cluster File System (Oracle ACFS) |
No
|
No
|
Yes for Oracle Database 11g?Release 2 (11.2) and for Hub Nodes for Oracle Database 12c?Release 1 (12.1) and later.
No for running Oracle Database on Leaf Nodes.
|
Yes for Oracle Database 12c?Release 1 (12.1) and later
|
Yes for Oracle Database 12c?Release 1 (12.1) and later
|
| Local file system |
No
|
Yes
|
Yes
|
No
|
No
|
|
OCFS2
|
No
|
No
|
Yes
|
Yes
|
Yes
|
|
Network file system (NFS) on a certified network-attached storage (NAS) filer
Note:?Direct NFS Client does not support Oracle Clusterware files
|
No
|
Yes
|
Yes
|
Yes
|
Yes
|
| Direct-attached storage (DAS) |
No
|
No
|
Yes
|
Yes
|
Yes
|
|
Shared disk partitions (block devices or raw devices)
|
No
|
No
|
No
|
No
|
No
|
ASM冗余方式：
在11G基礎上，增加冗余方式：彈性冗余（Flex），支持修改數據庫文件冗余。
冗余方式有3種：External、Normal、High、Flex。
OCR和Voting Disk需要磁盤數量對應冗余：1、3、5、3。
數據文件和恢復文件存放，需要磁盤數量對應冗余為1、2、3、3。
Table 8-1 Oracle ASM Disk Space Minimum Requirements for Oracle Database
Table 8-2 Oracle ASM Disk Space Minimum Requirements for Oracle Database (non-CDB)
注意點：
1、單個磁盤的大小不要大于2T（2000G），因為超過2T的磁盤無法創建磁盤組。
2、盡量使用多塊大小相同的磁盤創建同一磁盤組，這樣做的好處有兩點：
a.磁盤頭部損壞時方便更換，減少數據損壞風險。
b.如果大小不統一，容易導致磁盤組剩余容量足夠但不能使用的問題。
3、為ASM磁盤組增加磁盤時，會導致rebalance，占用IO資源，盡量在非生產時間添加磁盤。
外部冗余磁盤組（external disgroup）操作
1.創建磁盤組
例1
sqlplus / as sysasm create diskgroup dgroup_01 external redundancy disk '/devices/disks/c*';
例2
sqlplus / as sysasm create diskgroup DATADG external redundancy disk '/dev/asm-diskb' ATTRIBUTE 'compatible.rdbms'='11.2','compatible.asm'='11.2';
2.給磁盤組加盤
su - grid
sqlplus / as sysasm
alter diskgroup 磁盤組的名字 ?add disk ?‘/dev/rhdisk5’?rebalance power 5;
或者?alter diskgroup 磁盤組的名字 ?add disk ?‘/dev/rhdisk5’ ?named DISK5,add disk ?‘/dev/rhdisk6’ named DISK6;
3.給磁盤組刪盤
su - grid
sqlplus / as sysasm
alter diskgroup drop disk data_01;
4.撤銷刪除動作
su - grid
sqlplus / as sysasm
alter diskgroup data undrop disk;
5.修改asm磁盤大小
*asm中的磁盤也可以resize，需要注意：增大磁盤大小要確定對應的裸卷具有足夠空間，減少空間要確保剩余的空間足以存放數據量大小，否則會報錯
例：
alter diskgroup data resize disk data_01 ? size 1024m;
6.rebalance
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，但占用資源越多
power:0~11 ? ??，?0代表不做?rebalance
11.2.0.2?版本上限為?1024
查看rebalance進度
select operation,state,power,actual,sofar,est_work,est_minutes from v$asm_operation;
快速rebalance方法
sqlplus / as sysasm
startup restrict;
alter diskgroup dgext11gasm mount restricted;
alter diskgroup dgext11gasm rebalance power 10;
shutdown immediate;
startup
7.mount/dismount
alter diskgroup data mount/unmount
*以上操作只在當前實例掛載磁盤組，如果想每個實例都掛載，需要分別在各個實例中執行！
alter diskgroup all mount/dismount
掛載/卸載所有的磁盤組。
8.刪磁盤組（drop diskgroup）
drop diskgroup data
*需要磁盤組mount狀態，對于多節點的diskgroup,只能在一個asm實例上掛載之后才能被drop，其他節點必須dismount。
另：drop diskgroup data including contents;
9.disk online
alter diskgroup DATA online disk ‘diskname’;
或者：alter diskgroup DATA?online ?all;
10.磁盤組的屬性調整
alter diskgroup data set attribute ‘DISK_REPAIR_TIME’=‘12h’;
11.文件別名操作
加別名
ALTER DISKGROUP disk_group_1 ADD ALIAS ‘+disk_group_1/my_dir/my_file.dbf’ FOR ‘+disk_group_1/mydb/datafile/my_ts.342.3’;
改別名
ALTER DISKGROUP disk_group_1 RENAME ALIAS ‘+disk_group_1/my_dir/my_file.dbf’ TO ‘+disk_group_1/my_dir/my_file2.dbf’;
刪別名
ALTER DISKGROUP disk_group_1 DELETE ALIAS ‘+disk_group_1/my_dir/my_file.dbf’;
刪文件
ALTER DISKGROUP disk_group_1 DROP FILE ‘+disk_group_1/my_dir/my_file.dbf’;
六、使用NORMAL冗余磁盤組的操作
EXTERNAL means allow the underlying physical disk array do the mirroring
NORMAL ? ?means ASM will create one additional copy of an extent for redundancy
HIGH ? ? ? ? ?means ASM will create two additional copies of an extent for redundancy
由于使用extent進行冗余，這種特性允許各?failure group總容量可以不一致
要改變冗余度，需要新建磁盤組
USABALE_FILE_MB = (FREE_MB - REQUIRED_MIRROR_FREE_MB) / 2
1.查看failure group
select??name,total_mb,free_mb,GROUP_NUMBER,DISK_NUMBER,path,FAILGROUP,MOUNT_STATUS,HEADER_STATUS
from v$asm_disk order by FAILGROUP
2.創建磁盤組
sqlplus / as asmsys
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’;
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’;
3.給磁盤組加盤
alter diskgroup DATA1 add failgourp data1f2 disk ‘/dev/fg21’ name data1f2;
*如果磁盤有盤頭信息時加入會報錯
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15033: disk ‘/dev/fg21’ belongs to diskgroup “DATA1”
此時可以用force選項加盤，但注意會清掉磁盤頭
alter diskgroup data1 add failgroup data1f2 disk ‘/dev/fg21’ name data1f2 force;
4.disk online
alter diskgroup data1 online disk f2d1;
5.EXTENT RAC提升讀取速度
在對有?failure group的讀取時，默認是先讀?primary copy?，由于?primary copy是交替寫的，對于存儲距離很遠不合適，?11.1?之后提供參數調整為
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’;
則每個實例優先讀本地存儲，適合?extend rac情況
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