/dev/dm-0 ....(/dev/mapper机制)

另外参考:https://www.cnblogs.com/aozhejin/p/16061309.html

截取重点理解

dm实际对应的那些设备，一般都位于 /dev/mapper下面

这里有段英文：
when udev support is enabled in LVM, the /dev/mapper/ isa symlink to /dev/dm-X (this was chosen to comply with udev requirements)
https://listman.redhat.com/archives/linux-lvm/2010-July/msg00027.html

[root@itpux1 ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sdb softvg lvm2 a-- 50.00g 0
/dev/sdc oravg lvm2 a-- 30.00g 0
[root@itpux1 ~]#
[root@itpux1 ~]#
[root@itpux1 ~]# vgs
VG #PV #LV #SN Attr VSize VFree
oravg 1 1 0 wz–n- 30.00g 0
softvg 1 1 0 wz–n- 50.00g 0
[root@itpux1 ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
oralv oravg -wi-ao---- 30.00g
softlv softvg -wi-ao---- 50.00g

[root@itpux1 ~]# ls /dev/mapper -l
total 0
crw------- 1 root root 10, 236 May 3 08:34 control
lrwxrwxrwx 1 root root 7 May 3 08:34 oravg-oralv -> …/dm-1
lrwxrwxrwx 1 root root 7 May 3 08:34 softvg-softlv -> …/dm-0

[root@itpux1 ~]# cat /proc/devices|grep mapper
251 device-mapper