Red Hat Knowledgebase

Release Found:Red Hat Enterprise Linux 4 and 5

When devices are brought under the control of device-mapper-multipath the new multipathed devices can be seen in three different places under the /dev directory: /dev/dm-N, /dev/mapper/mpathN and /dev/mpath/mpathN.

• The /dev/dm-N devices are internal to device mapper and should never be used. These devices are not persistent. Starting with Red Hat Enterprise Linux 5, these devices are no longer created by udev.
• The /dev/mpath/mpathN devices are provided so that all the multipathed devices can be seen in one place. However, these device nodes may not be created on boot before the system needs to access them. Therefore they should not be used for creating logical volumes or filesystems.
• The /dev/mapper/mpathN devices are persistent and they are created early in the boot process. Therefore these are the device names that should be used to access the multipathed devices.