asm lib configuration on mapper design

ORACLEASM_SCANORDER="mpath dm" (OR ORACLEASM_SCANORDER="dm")

I found this on various documents on oracle site , still we will crosscheck with oracle once .

Also the below document

(How to Force ASM to Scan the Multipathed Device First using ASMLIB/oracleasm on RHEL 5/OL 5 and RHEL 6/OL 6 (Doc ID 1679409.1)

ASMLib/oracleasm can only be implemented on Linux OS.  When using multipathing, you want to FORCE oracleasm to scan the multipathed devices first

Below is the process mentioned

On all nodes:

1)  Shutdown all (DB and ASM):
You should stop all before restart ASMLib (eg: DB, ASM and HAS (crsctl stop crs for RAC) if you are in 11.2 - crsctl stop has) 

Then, on each node, one at a time, do the following steps that are dependent on the type of multipathing software:

2)  For backup, make a copy of your current /etc/sysconfig/oracleasm and /etc/sysconfig/oracleasm-_dev_oracleasm files

a) If using DM-Multipathing or Linux OS Native Multipathing:

1. Then, you want to change the following parameters in the  /etc/sysconfig/oracleasm-_dev_oracleasm file to which the /etc/sysconfig/oracleasm file is really linked to:

For example:

lrwxrwxrwx 1 root root 24 Jun 13 09:58 /etc/sysconfig/oracleasm -> oracleasm-_dev_oracleasm

# ORACLEASM_SCANORDER: Matching patterns to order disk scanning
ORACLEASM_SCANORDER="mpath dm" (OR ORACLEASM_SCANORDER="dm")

# ORACLEASM_SCANEXCLUDE: Matching patterns to exclude disks from scan
ORACLEASM_SCANEXCLUDE="sd"

 b) If using  EMC PowerPath Multipathing:

2. Then, you want to change the following parameters in the  /etc/sysconfig/oracleasm-_dev_oracleasm file to which the /etc/sysconfig/oracleasm file is really linked to:

For example:

lrwxrwxrwx 1 root root 24 Jun 13 09:58 /etc/sysconfig/oracleasm -> oracleasm-_dev_oracleasm

# ORACLEASM_SCANORDER: Matching patterns to order disk scanning
ORACLEASM_SCANORDER="emcpower"

# ORACLEASM_SCANEXCLUDE: Matching patterns to exclude disks from scan
ORACLEASM_SCANEXCLUDE="sd"