Implementing UDEV rules for setting disk permission on ASM disks

 Error Message :

Connection Failed!!!

ORA-00604: error occurred at recursive SQL level 1

ORA-01115: IO error reading block from file  (block # )

ORA-01110: data file 1: '+DATA01/Prd605/datafile/system.259.817302197'

ORA-15081: failed to submit an I/O operation to a disk

The oracle database Prd605 is down, My 11gr2 database on RHEL 6.3. When we checked the alert log file of the database, we came to know that the asm raw file /dev/dm-16 is not accessible.Also the permissions of the /dev/dm-* are changed to root:disk instead of oracle:oinstall.

Root Cause:

ASM could not communicate to the Database due to all existing ASM disks went to read only mode and permissions are changed to ROOT after multipath reload.

To fix this issue, we have defined necessary udev rules to preserve ownership permission while reloading multipath service

Solution:

1.   Create a file with the UDEV rules for raw device permission setting should be placed into rule files under the directory/etc/udev/rules.d/

2.   The file should contain the default system rules contained in the 

50-udev-permissions.rules file

3.   Add the below content in the above file (Note: Change the {DM_NAME}==”____“ according to the disk name)

ENV{DM_NAME}=="ASM?*", OWNER:="oracle", GROUP:="oinstall", MODE:="660"

4.   start the start_udev service

[root@linux1]# start_udev

Starting udev:      [  OK  ]

[root@linux1]#