LINUX上安装11.2.0.4 RAC时，安装grid运行root.sh报错ORA-15020 discovered duplicate ASM disk排查。
[root@lnx67 rules.d]# ls -al /dev/asm*
brw-rw—- 1 grid asmadmin 250, 0 Jan 5 14:47 /dev/asm-diskb
brw-rw—- 1 grid asmadmin 250, 16 Jan 5 14:47 /dev/asm-diskc
brw-rw—- 1 grid asmadmin 250, 32 Jan 5 14:47 /dev/asm-diskd
修改UDEV规则，将ASM使用的盘名字改为：
[root@lnx67 Packages]# ls -al /dev/asm*
brw-rw—- 1 grid asmadmin 250, 16 Jan 6 08:24 /dev/asm-diskarch
brw-rw—- 1 grid asmadmin 250, 0 Jan 5 14:47 /dev/asm-diskb
brw-rw—- 1 grid asmadmin 250, 16 Jan 5 14:47 /dev/asm-diskc
brw-rw—- 1 grid asmadmin 250, 32 Jan 5 14:47 /dev/asm-diskd
brw-rw—- 1 grid asmadmin 250, 32 Jan 6 08:24 /dev/asm-diskdata
brw-rw—- 1 grid asmadmin 250, 0 Jan 6 08:45 /dev/asm-diskocr
此时原来的绑定规划生成的盘符没有消失，新的盘符产生了。
之后安装GRID运行root.sh时报错：
ORA-15018: diskgroup cannot be created
ORA-15020: discovered duplicate ASM disk “DGOCR_0000”
——-2016/2/29帮人查问题发现最新信息： 12cR1安装时同样问题，只报错ORA-15018:这一行。。。
原因就是使用ASM_DISKSTRING参数是/dev/asm*,此时比如同一磁盘B对应了/dev/asm-diskb及/dev/asm-diskocr。
从操作系统层面使用start_udev，旧的没产生，最终是重启解决盘符问题。
GRID安装出错后，新安装环境就使用了重新安装的方式。
————root.sh报错信息
[root@lnx67 Packages]# sh /u01/11.2.0/grid/root.sh
Performing root user operation for Oracle 11g
The following environment variables are set as:
ORACLE_OWNER= grid
ORACLE_HOME= /u01/11.2.0/grid
Enter the full pathname of the local bin directory: [/usr/local/bin]:
Copying dbhome to /usr/local/bin …
Copying oraenv to /usr/local/bin …
Copying coraenv to /usr/local/bin …
Creating /etc/oratab file…
Entries will be added to the /etc/oratab file as needed by
Database Configuration Assistant when a database is created
Finished running generic part of root script.
Now product-specific root actions will be performed.
Using configuration parameter file: /u01/11.2.0/grid/crs/install/crsconfig_params
Creating trace directory
User ignored Prerequisites during installation
Installing Trace File Analyzer
OLR initialization – successful
root wallet
root wallet cert
root cert export
peer wallet
profile reader wallet
pa wallet
peer wallet keys
pa wallet keys
peer cert request
pa cert request
peer cert
pa cert
peer root cert TP
profile reader root cert TP
pa root cert TP
peer pa cert TP
pa peer cert TP
profile reader pa cert TP
profile reader peer cert TP
peer user cert
pa user cert
Adding Clusterware entries to upstart
CRS-2672: Attempting to start ‘ora.mdnsd’ on ‘lnx67’
CRS-2676: Start of ‘ora.mdnsd’ on ‘lnx67’ succeeded
CRS-2672: Attempting to start ‘ora.gpnpd’ on ‘lnx67’
CRS-2676: Start of ‘ora.gpnpd’ on ‘lnx67’ succeeded
CRS-2672: Attempting to start ‘ora.cssdmonitor’ on ‘lnx67’
CRS-2672: Attempting to start ‘ora.gipcd’ on ‘lnx67’
CRS-2676: Start of ‘ora.cssdmonitor’ on ‘lnx67’ succeeded
CRS-2676: Start of ‘ora.gipcd’ on ‘lnx67’ succeeded
CRS-2672: Attempting to start ‘ora.cssd’ on ‘lnx67’
CRS-2672: Attempting to start ‘ora.diskmon’ on ‘lnx67’
CRS-2676: Start of ‘ora.diskmon’ on ‘lnx67’ succeeded
CRS-2676: Start of ‘ora.cssd’ on ‘lnx67’ succeeded
Disk Group dgocr creation failed with the following message:
ORA-15018: diskgroup cannot be created
ORA-15020: discovered duplicate ASM disk “DGOCR_0000”
Configuration of ASM … failed
see asmca logs at /u01/app/oracle/cfgtoollogs/asmca for details
Did not succssfully configure and start ASM at /u01/11.2.0/grid/crs/install/crsconfig_lib.pm line 6912.
/u01/11.2.0/grid/perl/bin/perl -I/u01/11.2.0/grid/perl/lib -I/u01/11.2.0/grid/crs/install /u01/11.2.0/grid/crs/install/rootcrs.pl execution failed
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