In this video, you'll learn about DeviceMapper,
a generic kernel system used behind logical volume.
So DeviceMapper is a system that the kernel uses
to interface storage devices.
And it's used by a whole range of storage devices,
including Logical Volume Manager, Stratis,
which we'll cover later, Multipath,
which is used in storage area networks, and more systems.
Instead of taking care of all these systems individually,
the kernel provides one generic interface,
and that's the DeviceMapper.
This DeviceMapper generates non-persistent names,
like devdm0 and devdm1.
Persistent names are provided as symbolic link
through the DevMapper directory.
So you get a name like dev-mapper-vgdata-lvdata,
which is the name of the logical volume.
But alternatively, there are also
the LVM-generated symbolic links,
like dev-vgdata-lvdata.
So what does that mean?
Well, that means the following.
If you check the last line in etcfs-step,
there you can see that in etcfs-step,
I'm mounting dev-vgdata-lvdata.
But when I'm using mount, there we
can see that it is mounted slash dev-mapper-vgdata-lvdata.
Now, does that make a difference?
No, not really.
And I will show you why.
If you use an ls minus l on dev-vgdata-lvdata
and on dev-mapper-vgdata-lvdata, then you
can see that both of them are symbolic links pointing
to the DeviceMapper device, dm2.
As mentioned, the DeviceMapper device may change.
But the name of the logical volume
is hard-coded within the logical volume.
And that's why you don't have to use through UUID.
Feel free to use any of these two names
to mount your logical volume persistently in etcfs-step.