通过asm来存储数据库文件,在linux下可以通过asmlib的方式来管理块设备,也可以直接使用裸设备来建立asm磁盘。在asmlib方式下,磁盘设备启动顺序和名称的改变不会影响到asm的使用,但如果直接使用裸设备会怎么样那?我们知道asm会在磁盘中存储与asm有关的元数据,通过这些元数据asm可以了解磁盘的相关信息,因此理论上裸设备名称的改变不会影响asm的正常使用。下面,通过实验来验证一下。
首先看以下,裸设备的配置文件
node1
[root@node1 ~]# cat /etc/udev/rules.d/60-raw.rules # Enter raw device bindings here. # # An example would be: # ACTION=="add", KERNEL=="sda", RUN+="/bin/raw /dev/raw/raw1 %N" # to bind /dev/raw/raw1 to /dev/sda, or # ACTION=="add", ENV{MAJOR}=="8", ENV{MINOR}=="1", RUN+="/bin/raw /dev/raw/raw2 %M %m" # to bind /dev/raw/raw2 to the device with major 8, minor 1. ACTION=="add", KERNEL=="sdb1", RUN+="/bin/raw /dev/raw/raw1 %N" ACTION=="add", KERNEL=="sdb2", RUN+="/bin/raw /dev/raw/raw2 %N" ACTION=="add", KERNEL=="sdb5", RUN+="/bin/raw /dev/raw/raw3 %N" ACTION=="add", KERNEL=="sdb6", RUN+="/bin/raw /dev/raw/raw4 %N" ACTION=="add", KERNEL=="sdb7", RUN+="/bin/raw /dev/raw/raw5 %N" ACTION=="add", KERNEL=="sdb8", RUN+="/bin/raw /dev/raw/raw6 %N" ACTION=="add", KERNEL=="sdb9", RUN+="/bin/raw /dev/raw/raw7 %N"node2:
[root@node2 rules.d]# cat 60-raw.rules # Enter raw device bindings here. # # An example would be: # ACTION=="add", KERNEL=="sda", RUN+="/bin/raw /dev/raw/raw1 %N" # to bind /dev/raw/raw1 to /dev/sda, or # ACTION=="add", ENV{MAJOR}=="8", ENV{MINOR}=="1", RUN+="/bin/raw /dev/raw/raw2 %M %m" # to bind /dev/raw/raw2 to the device with major 8, minor 1. ACTION=="add", KERNEL=="sdb1", RUN+="/bin/raw /dev/raw/raw1 %N" ACTION=="add", KERNEL=="sdb2", RUN+="/bin/raw /dev/raw/raw2 %N" ACTION=="add", KERNEL=="sdb5", RUN+="/bin/raw /dev/raw/raw3 %N" ACTION=="add", KERNEL=="sdb6", RUN+="/bin/raw /dev/raw/raw4 %N" ACTION=="add", KERNEL=="sdb7", RUN+="/bin/raw /dev/raw/raw5 %N" ACTION=="add", KERNEL=="sdb8", RUN+="/bin/raw /dev/raw/raw6 %N" ACTION=="add", KERNEL=="sdb9", RUN+="/bin/raw /dev/raw/raw7 %N"asm下的磁盘信息如下:
[oracle@node1 ~]$ export ORACLE_SID=+ASM1 [oracle@node1 ~]$ sqlplus / as sysdba SQL*Plus: Release 10.2.0.5.0 - Production on Sun Aug 31 12:55:25 2014 Copyright (c) 1982, 2010, Oracle. All Rights Reserved. Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production With the Partitioning, Real Application Clusters, OLAP, Data Mining and Real Application Testing options SQL> col name for a30 SQL> col label for a30 SQL> col path for a30 SQL> set linesize 200 SQL> / NAME LABEL PATH ------------------------------ ------------------------------ ------------------------------ DG1_0000 /dev/raw/raw3 DG2_0000 /dev/raw/raw4 DG3_0000 /dev/raw/raw5 DG3_0001 /dev/raw/raw6 DG4_0000 /dev/raw/raw7 /dev/raw/raw2 /dev/raw/raw1 7 rows selected. SQL> ho ssh node2 Last login: Sat Aug 30 17:56:54 2014 from node1 [oracle@node2 ~]$ export ORACLE_SID=+ASM2 [oracle@node2 ~]$ sqlplus / as sysdba SQL*Plus: Release 10.2.0.5.0 - Production on Sun Aug 31 12:56:38 2014 Copyright (c) 1982, 2010, Oracle. All Rights Reserved. Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production With the Partitioning, Real Application Clusters, OLAP, Data Mining and Real Application Testing options SQL> col name for a30 SQL> col label for a30 SQL> col path for a30 SQL> set linesize 200 SQL> select name,label,path from v$asm_disk order by 1; NAME LABEL PATH ------------------------------ ------------------------------ ------------------------------ DG1_0000 /dev/raw/raw3 DG2_0000 /dev/raw/raw4 DG3_0000 /dev/raw/raw5 DG3_0001 /dev/raw/raw6 DG4_0000 /dev/raw/raw7 /dev/raw/raw2 /dev/raw/raw1 7 rows selected.
SQL> select file_name,tablespace_name from dba_data_files; FILE_NAME TABLESPACE_NAME -------------------------------------------- ------------------------------ +DG4/easy/datafile/system.272.856543875 SYSTEM +DG4/easy/datafile/undotbs1.273.856543885 UNDOTBS1 +DG4/easy/datafile/sysaux.274.856543891 SYSAUX +DG4/easy/datafile/undotbs2.276.856543901 UNDOTBS2 +DG4/easy/datafile/users.277.856543905 USERS SQL> create table t1 (id number,name varchar2(20)) tablespace users; Table created. SQL> insert into t1 values(1,111); 1 row created. SQL> insert into t1 select * from t1; 1 row created. SQL> / 2 rows created. SQL> / 4 rows created. SQL> / 8 rows created. SQL> / 16 rows created. SQL> / 32 rows created. SQL> / 64 rows created. SQL> commit; Commit complete. SQL> select count(*) from t1; COUNT(*) ---------- 128 SQL> update t1 set id=rownum,name=rownum; 128 rows updated. SQL> commit; Commit complete.
修改裸设备的路径名称并重起集群
[root@node1 ~]# cat /etc/udev/rules.d/60-raw.rules # Enter raw device bindings here. # # An example would be: # ACTION=="add", KERNEL=="sda", RUN+="/bin/raw /dev/raw/raw1 %N" # to bind /dev/raw/raw1 to /dev/sda, or # ACTION=="add", ENV{MAJOR}=="8", ENV{MINOR}=="1", RUN+="/bin/raw /dev/raw/raw2 %M %m" # to bind /dev/raw/raw2 to the device with major 8, minor 1. ACTION=="add", KERNEL=="sdb1", RUN+="/bin/raw /dev/raw/raw1 %N" ACTION=="add", KERNEL=="sdb2", RUN+="/bin/raw /dev/raw/raw2 %N" ACTION=="add", KERNEL=="sdb5", RUN+="/bin/raw /dev/raw/raw7 %N" ACTION=="add", KERNEL=="sdb6", RUN+="/bin/raw /dev/raw/raw6 %N" ACTION=="add", KERNEL=="sdb7", RUN+="/bin/raw /dev/raw/raw5 %N" ACTION=="add", KERNEL=="sdb8", RUN+="/bin/raw /dev/raw/raw4 %N" ACTION=="add", KERNEL=="sdb9", RUN+="/bin/raw /dev/raw/raw3 %N"
[oracle@node1 ~]$ export ORACLE_SID=+ASM1 [oracle@node1 ~]$ sqlplus / as sysdba SQL*Plus: Release 10.2.0.5.0 - Production on Sun Aug 31 13:13:01 2014 Copyright (c) 1982, 2010, Oracle. All Rights Reserved. Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production With the Partitioning, Real Application Clusters, OLAP, Data Mining and Real Application Testing options SQL> col name for a30 SQL> col lable for a33 SQL> col path for a33 SQL> set linesize 222 SQL> col label for a31 SQL> / NAME LABEL PATH ------------------------------ ------------------------------- --------------------------------- DG1_0000 /dev/raw/raw7 DG2_0000 /dev/raw/raw6 DG3_0000 /dev/raw/raw5 DG3_0001 /dev/raw/raw4 DG4_0000 /dev/raw/raw3 /dev/raw/raw1 /dev/raw/raw2 7 rows selected. SQL> ho ssh oracle@node2 Last login: Sun Aug 31 12:56:27 2014 from node1 [oracle@node2 ~]$ export ORACLE_SID=+ASM2 [oracle@node2 ~]$ sqlplus / as sysdba SQL*Plus: Release 10.2.0.5.0 - Production on Sun Aug 31 13:14:31 2014 Copyright (c) 1982, 2010, Oracle. All Rights Reserved. Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production With the Partitioning, Real Application Clusters, OLAP, Data Mining and Real Application Testing options SQL> col name for a31 SQL> col label for a31 SQL> col path for a31 SQL> set linesize 211 SQL> select name,label,path from v$asm_disk order by 1; NAME LABEL PATH ------------------------------- ------------------------------- ------------------------------- DG1_0000 /dev/raw/raw3 DG2_0000 /dev/raw/raw4 DG3_0000 /dev/raw/raw5 DG3_0001 /dev/raw/raw6 DG4_0000 /dev/raw/raw7 /dev/raw/raw2 /dev/raw/raw1 7 rows selected. SQL> exit Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production With the Partitioning, Real Application Clusters, OLAP, Data Mining and Real Application Testing options [oracle@node2 ~]$ export ORACLE_SID=easy2 [oracle@node2 ~]$ sqlplus / as sysdba SQL*Plus: Release 10.2.0.5.0 - Production on Sun Aug 31 13:15:31 2014 Copyright (c) 1982, 2010, Oracle. All Rights Reserved. Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production With the Partitioning, Real Application Clusters, OLAP, Data Mining and Real Application Testing options SQL> select count(*) from t1; COUNT(*) ---------- 128 SQL> select min(id),max(id) from t1; MIN(ID) MAX(ID) ---------- ---------- 1 128
由此可见,裸设备路径和名称的改变不会影响asm的使用,但是,我们依然建议保持路径名称的稳定性,方便管理。