I am new to the world of Linux and recently came across logical volume management however am unsure if I have understood its function correctly. My understanding is that I have 3 physical devices or 3 partitions which I take it have to be primary partitions. These physical devices or partitions then form the volume group. The size of the volume group is a the sum of the physical devices or partitions.Once the volume group has been created, I can create logical volumes which I can grow dynamically depending on the requirements of the server.
Is there a minimum requirement to have 3 physical devices or partitions or can I have 2?
Do the physical devices or partitions have to be of equal sizing?
If I have 1 primary partition, 1 Extended partition and 3 logical partitions, can I still have logical volumes?
If I add a new harddrive to the server, can I increase the size of my volume group and thereby increasing the amount of space available for my logical volumes?