ASM is Unable to Detect ASMLIB Disks/Devices
Introduction:
We can detect ASMLIB devices/disks thru the ASM instance using the below steps.
How to detect ASM devices/disks:
1) First of all, please scan the disks (on all the nodes if RAC):
<HOSTNAME>.<DOMAIN_NAME>:+ASM:<oracle>:11g>/etc/init.d/oracleasm scandisks
Scanning system for ASM disks: OK ]
2) Second, make sure the disks can be listed :
<HOSTNAME>.<DOMAIN_NAME>:+ASM:<oracle>:11g>/etc/init.d/oracleasm listdisks
<DISK #1>
<DISK #2>
3) Query each disks:
<HOSTNAME>.<DOMAIN_NAME>:+ASM:<oracle>:11g>/etc/init.d/oracleasm querydisk <DISK #1>
Disk “<DISK #1>” is a valid ASM disk on device [3, 18]
<HOSTNAME>.<DOMAIN_NAME>:+ASM:<oracle>:11g>/etc/init.d/oracleasm querydisk <DISK #2>
Disk “<DISK #2>” is a valid ASM disk on device [3, 22]
4) Check if they exist at OS level:
<HOSTNAME>.<DOMAIN_NAME>:+ASM:<oracle>:11g>ls -l /dev/oracleasm/disks/<DISK #1>
brw-rw—- 1 <oracle> <dba> 3, 18 Aug 13 09:54 /dev/oracleasm/disks/<DISK #1>
<HOSTNAME>.<DOMAIN_NAME>:+ASM:<oracle>:11g>ls -l /dev/oracleasm/disks/<DISK #2>
brw-rw—- 1 <oracle> <dba> 3, 22 Aug 13 09:55 /dev/oracleasm/disks/<DISK #2>
5) Then, in the initialization parameter file set the discovery disks string parameter as follow:
asm_diskstring =ORCL:*
Note: Also, you can set it thru the DBCA (during the diskgroup(s) creation) by pressing the [Change Disk Discovery Path] button.
6) If the problem persists, please open a new service request with Oracle support and then please provide us the next information (from all the nodes if RAC) :
Upload the next files:
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=)> /var/log/messages
=)> New /etc/sysconfig/oracleasm
=)> alert+ASM#.log for each instance.
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And the output of the next commands
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$> cat /etc/*release
$> uname -a
$> rpm -qa |grep oracleasm
$> df -ha
$> ls -l /dev/oracleasm/disks
$> powermt display dev=emcpower# (On all the partitions if using PowerPath from EMC)
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$> /etc/init.d/oracleasm status
$> usr/sbin/oracleasm-discover
$> /usr/sbin/oracleasm-discover ‘ORCL:*’
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SQL> show parameter asm
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