Not a tutorial, just few lines to write down what I've done.

This command gives you information about all virtual groups

Then, to create a logical group :

the -l option specifies the number of extent to allocate for this lv . You can see the number of available extents for a vg with the command above. This is useful to know when you want to create a lv using all the available space.

Then let's create an xfs fs on this lv : <code>