Multipath에서 /dev/dm-x 와 /dev/mpath/mpathN과 /dev/mapper/mpathN은 각각 무엇인가?

[원본] http://m.cafe.daum.net/redhat/DK8U/62?listURI=%2Fredhat%2FDK8U

Multipath에서 /dev/dm-x 와 /dev/mpath/mpathN과 /dev/mapper/mpathN은 각각 무엇인가?

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. 

 장치가 device-mapper-multipath의 제어하에 놓이면 새로운 다중 경로 장치는 /dev 디렉토리 아래의 /dev/dm-N, /dev/mapper/mpathN 및 /dev/mpath/mpathN에서 볼 수 있습니다. .

/dev/dm-N 장치는 장치 매퍼에 내장되어 있으므로 절대로 사용해서는 안됩니다. 이러한 장치는 영구적이지 않습니다. Red Hat Enterprise Linux 5부터는 이러한 장치가 더 이상 udev에 의해 생성되지 않습니다.

/dev/mpath/mpathN 장치는 모든 다중 경로 장치를 한 곳에서 볼 수 있도록 제공됩니다. 그러나 시스템 노드가 액세스해야만 부팅되기 전에 이러한 장치 노드가 만들어지지 않을 수 있습니다. 따라서 논리 볼륨이나 파일 시스템을 만드는 데 사용해서는 안됩니다.

/dev/mapper/mpathN 장치는 영구적이며 부팅 프로세스 초기에 만들어집니다. 따라서 다중 경로 장치에 액세스 할 때 사용해야 하는 장치 이름입니다.