Container
From Linux Raid Wiki
A container is a collection of devices that are managed as a set.
The set of devices may contain a number of different RAID arrays. For example, a container may contain a RAID10 array that expands 4 disks and at the same time a RAID 5 volume also shares those 4 disks. However, those arrays do not share the same data blocks. Within the container, there is one set of metadata that describes all of the arrays that reside in the container.
