Dynamic Multi-Pathing 7.3.1 Administrator's Guide - Linux

To remove devices from Device Mapper Multipath control and enable DMP

1. Stop the applications that use Device Mapper Multipath devices.
2. Unmount all the file systems that use Device Mapper Multipath devices.
3. Disable all the volumes on Device Mapper Multipath devices.

   # lvchange -a n lvname

4. Update the /etc/multipath.conf file to blacklist all device mapper devices. This step disables multi-pathing for all devices.

   # Blacklist all devices by default. 
   blacklist {
           devnode "*" 
   }

5. Restart multipathd to remove all /dev/dm-* and /dev/mpath/* device entries.

   For RHEL 7, SLES 12, and supported RHEL distributions:

   # systemctl restart multipathd

   For earlier versions of RHEL, SLES and supported RHEL distributions:

   # service multipathd restart

6. Stop the multipathd daemon.

   For RHEL 7, SLES 12, and supported RHEL distributions:

   # systemctl stop multipathd

   For earlier versions of RHEL, SLES and supported RHEL distributions:

   # service multipathd stop

7. Prevent multipathd from starting after reboot.

   For RHEL 7, SLES 12, and supported RHEL distributions:

   # systemctl disable multipathd

   For earlier versions of RHEL, SLES and supported RHEL distributions:

   # chkconfig multipathd off

8. Turn on the DMP support for the LVM volume groups.

   # vxdmpadm settune dmp_native_support=on

   The above command also enables DMP support for LVM root.

   This step can take some time depending upon the number of LVs.

9. Mount the file systems.
10. Restart the applications.