Multipathing installation and configuration in OEL

Multipathing installation and configuration in OEL (Oracle Enterprise Linux):

Problem information:

1. Check the multipath status:
# multipath -ll

Error:
dm multipath kernel driver not loaded oracle linux
/etc/multipath.conf file does not exists
run /sbin/mpathconf for creation of /etc/multipath.conf  file in the system.
a sample file exists at /usr/share/doc/device-mapper-multipath-0.4.9/multipath.conf path.

2. Run another command to check the multipath modules:
# multipath -v2
messages:
the multipath module is not loaded
Starting multipathd daemon: DM multipath kernel driver not loaded
etc...etc...

3. Check if published Luns are visible or not:
# multipath -ll
Luns will not be visible.

Solution:

1. Create the repo of OS ISO.

2. Check available multipath packages:
# yum list all | grep multip
device-mapper-multipath.x86_64         0.4.9-64.0.1.el6                     @dvd
device-mapper-multipath-libs.i686      0.4.9-64.0.1.el6                     @dvd
device-mapper-multipath-libs.x86_64    0.4.9-64.0.1.el6                     @dvd

3. Install all above packages:
# yum install device-mapper-multipath.x86_64 device-mapper-multipath-libs.i686 device-mapper-multipath-libs.x86_64

4. Run below commands to load kernel module:
# modprobe dm-multipath
# service multipathd start
# multipath -v2

5. Check if published Luns are visible or not:
# multipath -ll
Luns should be visible now.

6. Now you need to detect/scan the assigned LUNs published on the server.