ASM Disks not Reachable After Reboot - Manually Loading ASM Driver

After a system reboot if you see ASM disks are not available, and scanning ASM disk returns “Unable to instantiate disk”, as follows, it could be because oracleasm driver was not loaded and hence ASM did not work as expected. As a result, ASM disks will not be visible to ASM instance and ASM diskgroups would not mounted. Following is the example output of if you execute “oracleasm scandisks” command.

[root /]# oracleasm scandisks [root /]# oracleasm scandisks Reloading disk partitions: done Cleaning any stale ASM disks... Scanning system for ASM disks... Instantiating disk "DATA0" Unable to instantiate disk "DATA0" Instantiating disk "DATA1" Unable to instantiate disk "DATA1" Instantiating disk "DATA2" Unable to instantiate disk "DATA2" Instantiating disk "DATA4" Unable to instantiate disk "DATA4" Instantiating disk "DATA3" Unable to instantiate disk "DATA3" Instantiating disk "DATA5" Unable to instantiate disk "DATA5" Instantiating disk "DATA6" Unable to instantiate disk "DATA6" Instantiating disk "DATA7" Unable to instantiate disk "DATA7" Instantiating disk "FRA01" Unable to instantiate disk "FRA01" Instantiating disk "DATA8" Unable to instantiate disk "DATA8" Instantiating disk "DATA10" Unable to instantiate disk "DATA10" Instantiating disk "DATA9" Unable to instantiate disk "DATA9"

To solve this problem. You can either manually load the ASM driver, or follow recommendations of configuring the oracleasm driver using “oracleasm configure” command, as explained here.

To manually loading oracleasm driver. Execute following as root

-- Check status of driver [root ~]$ oracleasm status Checking if ASM is loaded: no Checking if /dev/oracleasm is mounted: no -- As you can see that driver is not loaded. Load the driver as follows [root ~ ]$ oracleasm init Loading module “oracleasm”: oracleasm Configuring “oracleasm” to use device physical block size Mounting ASMlib driver filesystem:  /dev/oracleasm [root ~]$ oracleasm status Checking if ASM is loaded: yes Checking if /dev/oracleasm is mounted: yes -- After this, excecute scan disk to re-scan the disks [root ~]$ oracleasm scandisks Reloading disk partitions: done Cleaning any stale ASM disks... Scanning system for ASM disks... Instantiating disk "DATA0" Instantiating disk "DATA1" Instantiating disk "DATA2" Instantiating disk "DATA4" Instantiating disk "DATA3" Instantiating disk "DATA5" Instantiating disk "DATA6" Instantiating disk "DATA7" Instantiating disk "FRA01" Instantiating disk "DATA8" Instantiating disk "DATA10" Instantiating disk "DATA9"

Once this is done, you should be able to see the disks in the output of “oracleasm listdisks” command.

[root ~]$ oracleasm  [root ~]$ oracleasm listdisks DATA01 DATA02 DATA03 DATA04 DATA05 DATA06 DATA07 DATA08 DATA09 DATA10 DATA11 FRA01 FRA02