通過asm來存儲數據庫文件，在linux下可以通過asmlib的方式來管理塊設備，也可以直接使用裸設備來建立asm磁盤。在asmlib方式下，磁盤設備啓動順序和名稱的改變不會影響到asm的使用，但如果直接使用裸設備會怎麼樣那？我們知道asm會在磁盤中存儲與asm有關的元數據，通過這些元數據asm可以瞭解磁盤的相關信息，因此理論上裸設備名稱的改變不會影響asm的正常使用。下面，通過實驗來驗證一下。
首先看以下，裸設備的配置文件
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"
[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"
[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.
修改裸設備的路徑名稱並重起集羣
[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
由此可見，裸設備路徑和名稱的改變不會影響asm的使用，但是，我們依然建議保持路徑名稱的穩定性，方便管理。