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=====DM-Multipath in RHEL6=====

====Components====
^  Components  ^ Description ^
| **dm-multipath** kernel module  |Reroutes I/O and supports failover for paths and path groups.|
|  **mpathconf** utility  |Configures and enables device mapper multipathing.|
|  **multipath** command  | Lists and configures multipath devices. Normally started up with **/etc/rc.sysinit**, it can also be started up by a **udev** program whenever a block device is added or it can be run by the **initramfs** file system. |
|  **multipathd** daemon  | Monitors paths; as paths fail and come back, it may initiate path group switches. Provides for interactive changes to multipath devices. This must be restarted for any changes to the **/etc/multipath.conf** file.|
|  **kpartx** command  | Creates device mapper devices for the partitions on a device It is necessary to use this command for DOS-based partitions with DM-MP. The **kpartx** is provided in its own package, but the **device-mapper-multipath** package depends on it. |

====Installation and Configuration====
The basic procedure for configuring your system with DM-Multipath is as follows:
  - Install the **device-mapper-multipath** rpm.
  - Create the configuration file and enable multipathing with the [[:linux:linux-san:mpathconf |mpathconf]] command. You can also start the multipath daemon with this command if you do not need to edit the configuration file.
  - If necessary, edit the **multipath.conf** configuration file to modify default values and save the updated file.
  - Start the multipath daemon.

====Configure DM-Multipath to Ignore Local Disks====
[[:linux:linux-san:local-disks| Configure to ignore Local disks procedure ]]