9edd1e4c_NTFS__Logical_Disk_Manager__Type_of_Container_
[Extend:] You can use the free space after "R:" and the container will remain simple. If you were to use free space on another disk, the container type will be "spanned". [Add Mirror:] Adding a copy of "R:" will speed up time it takes to access and will provide a fault tolerance. [Type of Container:] 
Simple
S i m p l e
S p a n n e d
S t r i p e
M i r r o r
S t r i p e w i t h p a r i t y
M i r r o r e d S t r i p e ( n o t s h o w n )
NTFS: Logical Disk Manager