ASM基础知识

原创 yBmZlQzJ 2022-09-07

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ASM基础知识

ASM是Oracle 10g R2中为了简化Oracle数据库的管理而推出来的一项新功能，这是Oracle自己提供的卷管理器，主要用于替代操作系统所提供的LVM，它不仅支持单实例，同时对RAC的支持也是非常好。ASM可以自动管理磁盘组并提供有效的数据冗余功能。使用ASM（自动存储管理）后，数据库管理员不再需要对ORACLE中成千上万的数据文件进行管理和分类，从而简化了DBA的工作量，可以使得工作效率大大提高。

ASM它提供了以平台无关的文件系统、逻辑卷管理以及软RAID服务。ASM可以支持条带化和磁盘镜像，从而实现了在数据库被加载的情况下添加或移除磁盘以及自动平衡I/O以删除“热点”。它还支持直接和异步的I/O并使用Oracle9i中引入的Oracle数据管理器API（简化的I/O系统调用接口）。

ASM是做为单独的Oracle实例实施和部署，并且它只需要有参数文件，不需要其它的任何物理文件，就可以启动ASM实例，只有它在运行的时候，才能被其它数据访问。在Linux平台上，只有运行了OCSSD服务（Oracle安装程序默认安装）了才能和访问ASM。

使用ASM的好处

1、将I/O平均分部到所有可用磁盘驱动器上以防止产生热点，并且最大化性能。

2、配置更简单，并且最大化推动数据库合并的存储资源利用。

3、内在的支持大文件

4、在增量增加或删除存储容量后执行自动联系重分配

5、维护数据的冗余副本以提高可用性。

6、支持10g，11g的数据存储及RAC的共享存储管理

7、支持第三方的多路径软件

8、使用OMF方式来管理文件

ASM冗余

ASM使用独特的镜像算法：不镜像磁盘，而是镜像盘区。作为结果，为了在产生故障时提供连续的保护，只需要磁盘组中的空间容量，而不需要预备一个热备(hot spare)磁盘。不建议用户创建不同尺寸的故障组，因为这将会导致在分配辅助盘区时产生问题。ASM将文件的主盘区分配给磁盘组中的一个磁盘时，它会将该盘区的镜像副本分配给磁盘组中的另一个磁盘。给定磁盘上的主盘区将在磁盘组中的某个伙伴磁盘上具有各自的镜像盘区。ASM确保主盘区和其镜像副本不会驻留在相同的故障组中。磁盘组的冗余可以有如下的形式：双向镜像文件(至少需要两个故障组)的普通冗余(默认冗余)和使用三向镜像(至少需要3个故障组)提供较高保护程度的高冗余。一旦创建磁盘组，就不可以改变它的冗余级别。为了改变磁盘组的冗余，必须创建具有适当冗余的另一个磁盘组，然后必须使用RMAN还原或DBMS_FILE_TRANSFER将数据文件移动到这个新创建的磁盘组。

三种不同的冗余方式如下：

1、 外部冗余（external redundancy）：表示Oracle不帮你管理镜像，功能由外部存储系统实现，比如通过RAID技术；有效磁盘空间是所有磁盘设备空间的大小之和。

2、 默认冗余（normal redundancy）：表示Oracle提供2份镜像来保护数据，有效磁盘空间是所有磁盘设备大小之和的1/2 （使用最多）

3、 高度冗余（high redundancy）：表示Oracle提供3份镜像来保护数据，以提高性能和数据的安全，最少需要三块磁盘（三个failure group）；有效磁盘空间是所有磁盘设备大小之和的1/3，虽然冗余级别高了，但是硬件的代价也最高。

ASM进程

ASM实例除了传统的DBWR,LGWR,CKPT,SMON,PMON等进程还包含如下四个新后台进程：

RBAL：负责协调磁盘组的重新平衡活动(负责磁盘组均衡)

ARB0-ARBn：在同一时刻可以存在许多此类进程，它们分别名为ARB0、ARB1，以此类推，执行实际的重新平衡分配单元移动进程。

GMON：用于ASM磁盘组监控

O0nn 01-10：这组进程建立到ASM实例的连接,某些长时间操作比如创建数据文件,RDBMS会通过这些进程向ASM发送信息

ASMB与ASM 实例的前台进程连接，周期性的检查两个instance的健康状况。每个数据库实例同时只能与一个ASM实例连接，因此数据库只会有一个ASMB后台进程。如一个节点上有多个数据库实例，它们只能共享一个ASM实例。

RBAL用来进行全局调用，以打开某个磁盘组内的磁盘。ASMB进程与该节点的CSS守护进程进行通信，并接收来自ASM实例的文件区间映射信息。ASMB还负责为ASM实例提供I/O统计数据

CSS集群同步服务。要使用ASM，必须确保已经运行了CSS集群同步服务，CSS负责ASM实例和数据库实例之间的同步。

注意：ASM实例必须要先于数据库实例启动，和数据库实例同步运行，迟于数据库实例关闭。ASM 实例和数据库实例的关系可以是1：1，也可以是1：n。如果是1：n，最好为ASM 安装单独的ASM_HOME。

配置ASM监听实现远程管理

动态监听

查看ASM实例的监听内容

[grid@db53:/home/grid]$cat /oracle/app/11.2.0/grid/network/admin/listener.ora

# listener.ora Network Configuration File: /oracle/app/11.2.0/grid/network/admin/listener.ora

# Generated by Oracle configuration tools.

LISTENER =

(DESCRIPTION_LIST =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))

(ADDRESS = (PROTOCOL = TCP)(HOST = db53)(PORT = 1521))

)

ADR_BASE_LISTENER = /oracle/app/grid

ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER=ON # line added by Agent

编辑oracle客户端的tnsname配置

[oracle@db53:/home/oracle]$cd /oracle/app/oracle/product/11.2.0/network/admin/ [oracle@db53:/oracle/app/oracle/product/11.2.0/network/admin]$vi tnsnames.ora

增加如下内容

asm53 =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = db53)(PORT = 1521))

(CONNECT_DATA =

(SERVER = DEDICATED)

(SERVICE_NAME = +ASM)

(INSTANCE_NAME = +ASM)

(UR=A)

)

测试一下

[oracle@db53:/oracle/app/oracle/product/11.2.0/network/admin]$tnsping asm53

TNS Ping Utility for Linux: Version 11.2.0.4.0 - Production on 17-JUN-2019 05:32:07

Used parameter files:

Used TNSNAMES adapter to resolve the alias

Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = db53)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = +ASM) (INSTANCE_NAME = +ASM) (UR=A)))

OK (20 msec)

连接ASM实例

[oracle@db53:/oracle/app/oracle/product/11.2.0/network/admin]$sqlplus sys/oracle@asm53 as sysasm

SQL*Plus: Release 11.2.0.4.0 Production on Mon Jun 17 05:32:42 2019

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

With the Automatic Storage Management option

SQL> set line 100

SQL> select INSTANCE_NUMBER,INSTANCE_NAME,HOST_NAME from v$instance;

INSTANCE_NUMBER INSTANCE_NAME HOST_NAME

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

1 +ASM db53

静态监听

编辑grid监听内容

[grid@db53:/home/grid]$vi /oracle/app/11.2.0/grid/network/admin/listener.ora

新增如下内容

SID_LIST_LISTENER =

(SID_LIST =

(SID_DESC =

(GLOBAL_DBNAME = db01)

(ORACLE_HOME = /oracle/app/oracle/product/11.2.0)

(SID_NAME = db53)

)

(SID_DESC =

(GLOBAL_DBNAME = +ASM)

(ORACLE_HOME = /oracle/app/11.2.0/grid)

(SID_NAME = +ASM)

)

编辑oracle客户端的tnsname配置

[oracle@db53:/home/oracle]$cd /oracle/app/oracle/product/11.2.0/network/admin/ [oracle@db53:/oracle/app/oracle/product/11.2.0/network/admin]$vi tnsnames.ora

增加如下内容

asm53s =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = db53)(PORT = 1521))

(CONNECT_DATA =

(SERVER = DEDICATED)

(SERVICE_NAME = +ASM)

(INSTANCE_NAME = +ASM)

)

测试一下

[oracle@db53:/home/oracle]$tnsping asm53s

TNS Ping Utility for Linux: Version 11.2.0.4.0 - Production on 17-JUN-2019 05:51:27

Used parameter files:

Used TNSNAMES adapter to resolve the alias

Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = db53)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = +ASM) (INSTANCE_NAME = +ASM)))

OK (0 msec)

连接实例

[oracle@db53:/home/oracle]$sqlplus /nolog

SQL*Plus: Release 11.2.0.4.0 Production on Mon Jun 17 05:52:12 2019

SQL> conn sys/oracle@asm53s as sysasm

Connected.

SQL> select INSTANCE_NUMBER,INSTANCE_NAME,HOST_NAME,STATUS from v$instance;

INSTANCE_NUMBER INSTANCE_NAME HOST_NAME STATUS

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

1 +ASM db53 STARTED

远程访问ASM配置总结

1.在动态监听中，只有设置了(UR=A)才能够远程访问ASM实例；

2.在静态监听中，无论是否设置(UR=A)均可远程访问ASM实例，甚至可以使用easy connect方法方法ASM实例

同机迁移数据库从ASM到文件系统

/backup/oradata/orcl用于存放数据文件

/backup/archivelog用于存放归档日志

检查文件路径

数据文件路径：

[oracle@db53:/home/oracle]$sqlplus / as sysdba

SQL> select file_name from dba_data_files;

或者

SQL> select name from v$datafile;

NAME

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

+DGSYSTEM/orcl/datafile/system.262.1006205329

+DGSYSTEM/orcl/datafile/sysaux.263.1006205335

+DGSYSTEM/orcl/datafile/undotbs1.264.1006205339

+DGSYSTEM/orcl/datafile/users.266.1006205381

+DGDATA01/orcl/datafile/tjdata01.262.1006208847

+DGDATA01/orcl/datafile/tjdata01.263.1006208877

+DGDATA01/orcl/datafile/tbs01.264.1006225059

7 rows selected.

日志文件路径：

SQL> select member from v$logfile;

MEMBER

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

+DGSYSTEM/orcl/onlinelog/group_1.257.1006205325

+DGDATA01/orcl/onlinelog/group_1.257.1006205325

+DGSYSTEM/orcl/onlinelog/group_2.258.1006205325

+DGDATA01/orcl/onlinelog/group_2.258.1006205325

+DGSYSTEM/orcl/onlinelog/group_3.259.1006205325

+DGDATA01/orcl/onlinelog/group_3.259.1006205325

+DGSYSTEM/orcl/onlinelog/group_4.260.1006205325

+DGDATA01/orcl/onlinelog/group_4.260.1006205327

+DGSYSTEM/orcl/onlinelog/group_5.261.1006205327

+DGDATA01/orcl/onlinelog/group_5.261.1006205327

10 rows selected.

临时文件路径：

SQL> select file_name from dba_temp_files;

FILE_NAME

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

+DGSYSTEM/orcl/tempfile/temp.265.1006205351

控制文件路径：

SQL> select name from v$controlfile;

NAME

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

+DGSYSTEM/orcl/controlfile/current.256.1006205323

+DGDATA01/orcl/controlfile/current.256.1006205323

数据库进行备份

当前是归档模式，所以用在线备份的方式即可

SQL> archive log list;

Database log mode Archive Mode

Automatic archival Enabled

Archive destination USE_DB_RECOVERY_FILE_DEST

Oldest online log sequence 16

Next log sequence to archive 20

Current log sequence 20

SQL> alter system switch logfile;

System altered.

SQL> alter system checkpoint;

System altered.

开始备份

[oracle@db53:/backup]$rman target /

RMAN> CONFIGURE CONTROLFILE AUTOBACKUP ON;

RMAN> backup database format '/backup/rman/orcl_%s_%p_%t';

Starting backup at 18-JUN-19

allocated channel: ORA_DISK_1

channel ORA_DISK_1: SID=1537 device type=DISK

channel ORA_DISK_1: starting full datafile backup set

channel ORA_DISK_1: specifying datafile(s) in backup set

input datafile file number=00003 name=+DGSYSTEM/orcl/datafile/undotbs1.264.1006205339

input datafile file number=00001 name=+DGSYSTEM/orcl/datafile/system.262.1006205329

input datafile file number=00002 name=+DGSYSTEM/orcl/datafile/sysaux.263.1006205335

input datafile file number=00007 name=+DGDATA01/orcl/datafile/tbs01.264.1006225059

input datafile file number=00004 name=+DGSYSTEM/orcl/datafile/users.266.1006205381

input datafile file number=00005 name=+DGDATA01/orcl/datafile/tjdata01.262.1006208847

input datafile file number=00006 name=+DGDATA01/orcl/datafile/tjdata01.263.1006208877

channel ORA_DISK_1: starting piece 1 at 18-JUN-19

channel ORA_DISK_1: finished piece 1 at 18-JUN-19

piece handle=/backup/rman/orcl_1_1_1011286614 tag=TAG20190618T165654 comment=NONE

channel ORA_DISK_1: backup set complete, elapsed time: 00:00:56

Finished backup at 18-JUN-19

Starting Control File and SPFILE Autobackup at 18-JUN-19

piece handle=+DGRECOVERY/orcl/autobackup/2019_06_18/s_1011286670.263.1011286673 comment=NONE

Finished Control File and SPFILE Autobackup at 18-JUN-19

RMAN备份完成后，最好把控制文件单独备份一下

SQL> alter database backup controlfile to '/backup/rman/control.ctl';

SQL> alter database backup controlfile to trace as '/backup/rman/control.trc';

最终备份的文件都在这里：

[oracle@db53:/backup/rman]$ls -al

total 1100212

drwxr-xr-x 2 oracle oinstall 4096 Jun 17 06:20 .

drwxr-xr-x 3 oracle oinstall 4096 Jun 17 06:11 ..

-rw-r----- 1 oracle asmadmin 41828352 Jun 17 06:19 control.ctl

-rw-r--r-- 1 oracle asmadmin 7373 Jun 17 06:20 control.trc

-rw-r----- 1 oracle asmadmin 1084768256 Jun 17 06:15 orcl_1_1_1011161593

数据库迁移

更改控制文件路径

SQL> alter system set control_files='/backup/oradata/orcl/control01.ctl', '/backup/oradata/orcl/control02.ctl' scope=spfile;

System altered.

更改数据文件路径

SQL> alter system set db_create_file_dest='/backup/oradata/orcl' scope=spfile;

System altered.

SQL> alter system set db_create_online_log_dest_1='/oracle/oradata/orcl' scope=spfile;

System altered.

SQL> alter system set db_create_online_log_dest_2='/oracle/oradata/orcl' scope=spfile;

System altered.

更改归档日志路径

SQL> archive log list;

Database log mode Archive Mode

Automatic archival Enabled

Archive destination USE_DB_RECOVERY_FILE_DEST

Oldest online log sequence 17

Next log sequence to archive 21

Current log sequence 21

SQL> show parameter DB_RECOVERY_FILE_DEST

NAME TYPE VALUE

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

db_recovery_file_dest string +dgrecovery

db_recovery_file_dest_size big integer 1024G

SQL> alter system set db_recovery_file_dest='/backup/archivelog' scope=spfile;

System altered.

SQL> alter system set db_recovery_file_dest_size=10G scope=spfile;

System altered.

创建参数文件

SQL> show parameter pfile;

NAME TYPE VALUE

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

spfile string +DGSYSTEM/orcl/spfileorcl.ora

SQL> create pfile='/backup/pfileorcl.ora' from spfile;

File created.

重启数据库，从spfile启动

SQL> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> startup pfile='/backup/pfileorcl.ora' nomount;

ORACLE instance started.

Total System Global Area 3340451840 bytes

Fixed Size 2257840 bytes

Variable Size 788532304 bytes

Database Buffers 2533359616 bytes

Redo Buffers 16302080 bytes

创建一个spfile

SQL> create spfile from pfile='/back/pfileorcl.ora';

到目录下查看，已经创建成功spfile文件

[oracle@db53:/oracle/app/oracle/product/11.2.0/dbs]$pwd

/oracle/app/oracle/product/11.2.0/dbs

[oracle@db53:/oracle/app/oracle/product/11.2.0/dbs]$ls

hc_orcl.dat hc_neworcl.dat initorcl.ora init.ora lkORCL orapworcl snapcf_orcl.f spfileorcl.ora

重新启动数据库到nomount状态，查看pfile，已经从文件系统的spfile启动了

SQL> shutdown immediate

ORA-01507: database not mounted

ORACLE instance shut down.

SQL> startup nomount;

ORACLE instance started.

Total System Global Area 3340451840 bytes

Fixed Size 2257840 bytes

Variable Size 788532304 bytes

Database Buffers 2533359616 bytes

Redo Buffers 16302080 bytes

SQL> show parameter pfile;

NAME TYPE VALUE

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

spfile string /oracle/app/oracle/product/11.2.0/dbs/spfileorcl.ora

恢复控制文件

[oracle@db53:/oracle/app/oracle/product/11.2.0/dbs]$rman target /

RMAN> restore controlfile from '+DGSYSTEM/orcl/controlfile/current.256.1006205323'；

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03002: failure of restore command at 06/17/2019 06:51:56

RMAN-06172: no AUTOBACKUP found or specified handle is not a valid copy or piece

RMAN> show all

RMAN configuration parameters for database with db_unique_name ORCL are:

CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default

CONFIGURE BACKUP OPTIMIZATION OFF; # default

CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default

CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default

CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default

CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default

CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default

CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default

CONFIGURE MAXSETSIZE TO UNLIMITED; # default

CONFIGURE ENCRYPTION FOR DATABASE OFF; # default

CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default

CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default

CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default

RMAN> restore controlfile from '/backup/rman/orcl_1_1_1011161593';

Starting restore at 17-JUN-19

using channel ORA_DISK_1

channel ORA_DISK_1: restoring control file

channel ORA_DISK_1: restore complete, elapsed time: 00:00:01

output file name=/oracle/oradata/orcl/control01.ctl

Finished restore at 17-JUN-19

第二次操作的时候，直接从原有的控制文件进行恢复，因为RMAN配置过CONFIGURE CONTROLFILE AUTOBACKUP ON;

[oracle@db53:/home/oracle]$rman target /

Recovery Manager: Release 11.2.0.4.0 - Production on Tue Jun 18 17:21:45 2019

connected to target database: ORCL (not mounted)

RMAN> restore controlfile from '+DGSYSTEM/orcl/controlfile/current.256.1006205323';

Starting restore at 18-JUN-19

using target database control file instead of recovery catalog

allocated channel: ORA_DISK_1

channel ORA_DISK_1: SID=1521 device type=DISK

channel ORA_DISK_1: copied control file copy

output file name=/backup/oradata/orcl/control01.ctl

output file name=/backup/oradata/orcl/control02.ctl

Finished restore at 18-JUN-19

转换数据文件到文件系统

RMAN> alter database mount;

database mounted

released channel: ORA_DISK_1

RMAN> backup as copy database format 'backup/oradata/orcl/%U';

Starting backup at 18-JUN-19

using channel ORA_DISK_1