How do I determine which dm-X device maps to each device mapper device on Red Hat Enterprise Linux?
Issue
- The
iostat
command is reporting manydm
devices that do not exist any longer. They did un-present several LUNs, and did it cleanly. The devices do not show in/dev
, but they do see them undersys/block
. They do still have aliases in the multipath config file for the devices that are no longer present. How do I tell what device is what? - PV is created on top of
dm
device. How to find whichdm
device maps to which block device? - How to find which
dm-*
device maps to which LVM logical volume? - It's difficult to find which
dm-*
device maps to which LVM if there are too manydm-*
devices in the system. How to find the mapping relationship between them? - Need to map logical volumes to physical devices
- Need to find out which LVs are on which disks
Environment
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Several
device-mapper
managed devices (either device-mapper-multipath or LVM)
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