Unable to see Member disk in ASM through DBCA

Question

Hi
I am having standalone(NON-RAC) box with Linux AS3(Kernel Ver. 2.4.21.4) and oracle 10G installed on it. It is having one database as ORCL. Now i wants to configure ASM on it. For that I did the following activities.
mkdir -p /u03
mkdir -p /u03/asmdisks
dd if=/dev/zero of=/u03/asmdisks/disk0 bs=1024k number=100
dd if=/dev/zero of=/u03/asmdisks/disk1 bs=1024k number=100
dd if=/dev/zero of=/u03/asmdisks/disk2 bs=1024k number=100
dd if=/dev/zero of=/u03/asmdisks/disk3 bs=1024k number=100
chown -R oracle:oinstall /u03
chmod -R 777 /u03
Then i chose to create the database through DBCA. Where i gave database Sid as ASM and selected AUTOMATIC STORAGE MANAGEMENT for the storage. In the parameter of asm instance i set the parameter asm_diskstring as */u03/asmdisks/*'
ASM Instance gets started with this as when i do "ps -aux | grep +asm" then it shows the ASM processes.
Now when i create the diskgroup as DGROUP1 with normal redundancy, I am not able to see member disks which i have defined in ASM instance parameter "asm_diskstring".
Is there any need to install ASM libraries on OS or any special service should be started on the OS?
Kindly Help as i am struckup in this past 5 days.
Regards
Bally

Answer 1

Two issues come to mind. Invallid discovery string - which means that ASM fails to see the raw disks. Or incorrectly configured raw disks.
My guess is the latter. Those "devices" that you configured as ASM devices do not sound valid. They have to be dinkum raw devices - they cannot be binary files on a cooked file system. Unless I'm mistaken? (I cannot recall seeing any cooked files as ASM devices option when I did a couple of ASM installs)
Okay, not close to my Linux boxes to check so the following is frrom memory. The last ASM install I did on Redhat was to create an actual raw device use an unformatted partition (e.g. /dev/sdb1) using the raw device Linux command. A file called /etc/sysconfig/rawdevices was created. At boot time the raw devices are mounted in /dev/raw something or another. These devices are then chmod'ed so that the oracle o/s user can access them.
The ASM discovery string is then set to /dev/raw whatever to pick up these raw devices.