Is there any good resource which I can use to self-learn all the low-level system administration details on Grub, Grub2, disks, partitioning, LVM, etc? I'm comfortable with system admin tasks post-boot but I lack knowledge about both the fundamentals and actuals of all that happens during boot on a Linux system such as Fedora.

Any recommendations on how to setup a testbed on my desktop for learning the above? I may not be able to get another machine / harddisk, so may have to rely on something like VirtualBox. But don't know if there are other (better) options... so asking for tips from those who have self-learned / mastered this track themselves.