When root. sh meets ORA-15031

Recently handle an OracleGridinfrastructure (GI) installation problem, failed during the execution of root. sh, and displays the following error: DiskGroupOCRcreationfailedwiththefollowingmessage: ORA-15018: diskspecificationdevvxrdskdg_db01lv_vote1m

Recently, an Oracle Grid infrastructure (GI) installation problem was solved. sh process failed and the following error is displayed: DiskGroupOCRcreationfailedwiththefollowingmessage: ORA-15018: diskgroupcannotbecreatedORA-15031: diskspecification '/dev/vx/rdsk/dg_db01/lv_vote1' m

Recently, an Oracle Grid infrastructure (GI) installation problem was solved. The problem occurred while executing root. sh and the following error was displayed:

Disk Group OCR creation failed with the following message: ORA-15018: diskgroup cannot be createdORA-15031: disk specification '/dev/vx/rdsk/dg_db01/lv_vote1' matches no disks <
 
  
Error ORA-15031 prompt, still very obvious, can not identify the corresponding voting disk, the normal solution, is to check whether the disk is mounted normally, the permission is correct, etc., need to check one by one. If you search for Metalink, this error is generally caused by running root. sh on node2. node1 is normal. Most of them are permissions and system-level mounting problems. However, if this problem occurs, the execution of root. sh on node1.

Start various analysis checks:

1. Check whether the disk exists and the permission is correct. All Pass
  
#ls -lrt /dev/vx/rdsk/dg_db01crw-rw----    1 grid     asmadmin     40,60000 Feb 12 10:51 lv_vote1crw-rw----    1 grid     asmadmin     40,60001 Feb 12 10:52 lv_vote2crw-rw----    1 grid     asmadmin     40,60002 Feb 12 10:52 lv_vote3
  
2. Check asm_diskstring settings
  
SQL> show parameter asm_diskstringNAME                                 TYPE                              VALUE------------------------------------ --------------------------------- ------------------------------asm_diskstring                       string                            /dev/vx/rdsk/dg_db01
  
3. Use kfod to check whether the corresponding disk can be scanned.
  
 kfod asm_diskstring='/dev/vx/rdsk/dg_db01/lv_*' disks=all--------------------------------------------------------------------------------Disk          Size Path                                     User     Group  ================================================================================  1:     327680 Mb /dev/vx/rdsk/dg_db01/lv_data01           grid     asmadmin  2:     327680 Mb /dev/vx/rdsk/dg_db01/lv_data02           grid     asmadmin  3:     327680 Mb /dev/vx/rdsk/dg_db01/lv_data03           grid     asmadmin  4:     112910 Mb /dev/vx/rdsk/dg_db01/lv_data04           grid     asmadmin  5:       1024 Mb /dev/vx/rdsk/dg_db01/lv_vote1            grid     asmadmin  6:       1024 Mb /dev/vx/rdsk/dg_db01/lv_vote2            grid     asmadmin  7:       1024 Mb /dev/vx/rdsk/dg_db01/lv_vote3            grid     asmadmin--------------------------------------------------------------------------------ORACLE_SID ORACLE_HOME                                                          ================================================================================    +ASM1 /oracle/product/11.2.0.4/grid_1                                      grid@HAZZ-NRMS-RESDB01:/home/grid>
  
4. Now, I suspect that the asm_diskstring settings are not accurate enough to change it
  
SQL> show parameter asm_diskstringNAME                                 TYPE                              VALUE------------------------------------ --------------------------------- ------------------------------asm_diskstring                       string                            /dev/vx/rdsk/dg_db01/lv_*
  
But the problem persists,

5. Check the cluster installation environment and no problems are found.
  
$ ./runcluvfy.sh stage -pre crsinst -n node1,node2 -verbose$ ./runcluvfy.sh comp ssa -n all -verbose
  
6. Operating System logs, no errors found

  
IBM: /bin/errpt -a > messages.out
  
At this point, you can confirm that, according to the oracle Installation documentation, the current disk permissions fully comply with the installation conditions. In the GI graphical installation process, you can also see the ASM disk, but in the root. sh cannot be passed during execution.

And then query the following article through Metalink.
ASM Is Not Detecting Raw Devices Or Regular Raw Devices On AIX (Doc ID 1174604.1)

Description:
EMC storage, using multi-path, may encounter this problem, and my storage does use EMC and multi-path.

Okay, follow the Solution in this document to test it.

  
Please attempt the next action plan on the mount point which contains the ASM Oracle Home:1) Dismount the filesystem which contains the ASM Oracle Home.2) Change the ownership of the mount point to oracle : dba3) Remount the filesystem4) The EMC PowerPath raw devices or regular raw devices are now being discovered.
  
Follow these steps:

  
1. dismount/u01/oracle2, chown-R oracle: oinstall/u01/oracle chmod 775/u01/oracle3, mount/u01/oracle4, and run root. sh again.
  
To be honest, it is hard for me to understand why the permission to mount the path affects the unidentifiable ASM disk.

According to Bug 1174604.1: asm disk not getting discovered mentioned in Article 9976459, there is an explanation as follows:
  
When a file system is mounted over a directory, the permissions of the root directory of the mounted file system takes precedence over the permissions of  the mount point.A common problem is failure of the pwd command. Without search permission in the mounted-over directory, the pwd command returns the following message:pwd: Permission deniedThis problem can be avoided by always setting the permissions of the mounted-over directory to at least 111.
  
Finally, according to the above description, google explained to IBM:
Http://www-01.ibm.com/support/knowledgecenter/ssw_aix_71/com.ibm.aix.osdevice/mountpoint.htm

Installation Point
The Installation Point is a directory or file where you can access the new file system, directory, or file. To install the file system or directory, the installation point must be a directory; to install the file, the installation point must be a file.
Generally, the file system, directory, or file is installed on an empty Installation Point, but this is not necessary. If the file or directory of the Installation Point contains any data, the data is not accessible when another file or directory is installed at the installation point. In fact, the installed file or directory overwrites the content in the previous directory. Once you cancel the installation in the initial directory or file, the directory or file will be accessible again.
When a file system is installed in a directory, the root directory permission of the installed file system takes precedence over the security permission. One exception is the parent directory entry in the installation directory. To allow the operating system to access the new file system, the parent directory of the installation point must be available.
For example, if the current working directory is/home/frank, run the command cd .. to change the working directory to/home. If the/home/frank directory is the root of the installed file system, the operating system must find the parent directory information in the/home/frank directory to make the cd .. command successful.
For any command that requires the parent directory information to succeed, you must have the permission to search in the installation directory. Failure to grant search permission to the installation directory may result in unpredictable results, especially because the installation directory permission is invisible. The common problem is that the pwd command fails. If you do not have permission to search for the installation directory, the pwd command returns this message:
Pwd: Permission denied
You can avoid this problem by setting the installation directory permission to at least 111.

At this point, the problem has been solved. Due to the mount point permission problem, the recognition of ASM disk will fail.
Hey !!! Amazing experience !!!