ORA-17612 - Failed to discover Oracle Disk Manager library

Problem

On a HP-UX host with VXVM/CFS in use, we got following error when starting an Oracle RAC instance:

ORA-17612: Failed to discover Oracle Disk Manager library, return value 2

Nevertheless the corresponding library and link is present:

$ ll /opt/oracle/database/11.2.0.4.2_01/lib/libodm*
-rw-r--r--   1 oracle     oinstall     23898 Sep 29  2013 libodm11.a
lrwxr-xr-x   1 oracle     oinstall        26 Sep 16 09:26 libodm11.so -> /opt/VRTSodm/lib/libodm.so
lrwxr-xr-x   1 oracle     oinstall        12 Sep 16 09:26 libodm11.so.orginal -> libodmd11.so
-rwxr-xr-x   1 oracle     oinstall     76344 Sep 29  2013 libodmd11.so
$ ll /opt/VRTSodm/lib/libodm.so
-r-xr-xr-x   1 root       sys         199016 Sep 11  2013 /opt/VRTSodm/lib/libodm.so

Solution

ODM pseudo filesystem was not mounted due to missing kernel module:

# mount | grep odm

# mount -F odm /dev/odm /dev/odm

mount: odm : Invalid argument

# kcmodule -v odm

Module              odm  (50.0)
Description         ODM Driver
Timestamp           Wed Sep 04 12:36:27 2013 [523047AB]
State               unused <-----
State at Next Boot  unused
Capable             loaded static unused
Depends On          module fdd:0.0.0 interface HPUX_11_31_PERF:1.0

# kcmodule odm=loaded

	 ==> Update the automatic 'backup' configuration first? n
	   * Future operations will ask whether to update the backup.
	   * The requested changes have been applied to the currently
		 running configuration.
Module            State   Cause     Notes
odm     (before)  unused            loadable, unloadable
		(now)     loaded  explicit  

# kcmodule -v odm

Module              odm  (50.0)
Description         ODM Driver
Timestamp           Wed Sep 04 12:36:27 2013 [523047AB]
State               loaded (as requested)
State at Next Boot  loaded (as requested)
Capable             loaded static unused
Depends On          module fdd:0.0.0 interface HPUX_11_31_PERF:1.0

# grep odm /stand/system

module odm      loaded  50.0.[523047AB]

# mount | grep odm

/dev/odm on /dev/odm smartsync,dev=400001c on Tue Sep 09 06:28:29 2014