What Are Containers?
Containers are logical constructs of digital space that contain one or more volumes.
A volume that needs additional storage space can use free space from another container.
Coyote Moon, Inc.
Volume vs. Partition
A volume is a self-contained storage area that a computer can read.
Common types of volumes include CDs, DVDs,SSDs, andhard drives.
Volumes can be divided into one or morepartitions, which take up space on the hard drive.
A volume can span multiple physical discs or drives, but a partition is more restricted.
Unlike partitions, volumes can use free space from anywhere, which wasn’t possible before APFS.
APFS is optimized for certaindisk types, namely solid-state drives (SSDs).
Upgrading to APFS has limited benefits for computers with a hard disk drive.
It can house as many partitions and physical drives as needed.
A logical volume allocates and manages space on one or more mass storage devices.
It separates the operating system from the physical devices that make up the storage medium.
Both hardware controllers and software can create RAID arrays.
In both cases, the OS isn’t aware of what’s physically making up the logical volume.
It could be one drive, two drives, or many drives.
This setup allows for a more flexible data storage system.
Logical Volume Managers (LVMs)
Logical volumes can have partitions located on multiple physical storage devices.
Logical Volume Managers (LVMs) make these systems easier to use.
Since Apple introduced OS X Lion, macOS has used an LVM system known as Core Storage.
It was first used to provide the full-disk encryption system used by theApple File Vault 2 system.
