ASM and RedHat 5

I’m really angry on me because I spend another 30 min fighting with problem which I have already solved several times. Oracle ASMLib is looking for a disks using /dev/dm-* devices which are not created by default in Red Hat 5. But if you manually map any device as Oracle ASM disk it will be working until next reboot.

So if after reboot in Red Hat 5 your ASM disks disappear check if you done following things:

• Comment line in /etc/udev/rules.d/ 90-dm.rules

#KERNEL=="dm-[0-9]*", ACTION=="add", OPTIONS+="ignore_device"

it creates a /dev/dm-* devices after system reboot


• Check in /etc/sysconfig/oracleasm if disk are not excluded
  
  # ORACLEASM_ENABELED: 'true' means to load the driver on boot.
  ORACLEASM_ENABLED=true
  # ORACLEASM_UID: Default user owning the /dev/oracleasm mount point.
  ORACLEASM_UID=oracle
  # ORACLEASM_GID: Default group owning the /dev/oracleasm mount point.
  ORACLEASM_GID=oinstall
  # ORACLEASM_SCANBOOT: 'true' means scan for ASM disks on boot.
  ORACLEASM_SCANBOOT=true
  # ORACLEASM_SCANORDER: Matching patterns to order disk scanning
  ORACLEASM_SCANORDER=""
  # ORACLEASM_SCANEXCLUDE: Matching patterns to exclude disks from scan
  ORACLEASM_SCANEXCLUDE=""
  


• Check a file privileges

After that you should see your ASM disks.

Regards,
Marcin