How to Check Core Storage Volumes on macOS using diskutil

The CoreStorage Abstraction Layer

In older versions of macOS (prior to the introduction of the modern APFS filesystem), Apple relied heavily on an abstraction layer called CoreStorage. CoreStorage acts as a logical volume manager that sits between the physical hard drive hardware and the user-facing HFS+ filesystem. It is the underlying technology that made Apple’s Fusion Drive (combining a small SSD with a large HDD into a single volume) and FileVault full-disk encryption possible.

When a system administrator needs to diagnose a failing Fusion Drive, decrypt a volume via the command line, or manually delete a stubborn partition that Disk Utility refuses to touch, they must bypass the standard disk commands and interact directly with the CoreStorage databases using the Terminal.

Viewing the CoreStorage Hierarchy

The standard diskutil list command will show you the physical disks, but it will not provide the deeply nested UUIDs (Universally Unique Identifiers) required to manage a CoreStorage volume.

To view the logical hierarchy, you must run the specific CoreStorage list command:

diskutil cs list

Note: cs is the shorthand abbreviation for coreStorage.

Understanding the Output

The output of this command will display a highly nested tree structure, moving from the physical hardware up to the logical volume. It is critical to understand the three distinct layers:

1. Logical Volume Group (LVG): This is the master container. If you have a Fusion Drive, the LVG encompasses both the physical SSD and the physical HDD. It will have a massive alphanumeric UUID.
2. Physical Volume (PV): Nested underneath the LVG, you will see the actual physical hard drives that supply space to the group.
3. Logical Volume Family (LVF) / Logical Volume (LV): This is the final layer. This is the actual formatted partition that the user sees on their desktop (e.g., “Macintosh HD”). It has its own unique UUID.

Deleting a CoreStorage Volume

If you are wiping an old Mac for surplus, or if a Fusion Drive has completely corrupted its directory structure, the graphical Disk Utility will often throw an error when you click “Erase.” To forcefully destroy the volume and return the physical drives to a raw state, you must delete the entire Logical Volume Group.

First, run diskutil cs list and carefully copy the UUID string next to Logical Volume Group (e.g., 12345678-ABCD-EFGH-IJKL-1234567890AB).

Then, execute the delete command:

diskutil cs delete 12345678-ABCD-EFGH-IJKL-1234567890AB

The terminal will instantly unmount the volumes, destroy the CoreStorage abstraction layer, and reformat the physical drive(s) as standard, non-CoreStorage HFS+ partitions, allowing you to install a fresh operating system.