1- you need to have LCAP installed and running on your machine (even a 'NULL'
   which translates changelog to lcap records). This means you need to have at
   least package liblcap to build. The server is optional if you don't use
    the proxified channel.
2- you need to run Lustre with the 'jobid' patch (this patch is part of
   Lustre 2.7)
3- Before reading changelogs for the first time
        #lctl  --device lustre-MDT0000 changelog_register
4 - See changelogs (outside lcap) with a lfs command:
        # lfs changelog <fsname>-MDT0000
5- Clear changelogs manually (for a registered user (here cl1)
   up to a given index (here 3))
        #  lfs changelog_clear <fsname>-MDT0000 cl1 3
