8.1.2.4 Runtime Storage Driver

A runtime storage driver is the specific component responsible for actually implementing Docker's layered filesystem behavior — combining read-only image layers with a container's writable layer into a single, unified view — with overlay2 being the modern, commonly used default on Linux systems.

Identifying the Currently Active Storage Driver

The storage driver currently in use can be checked directly.

docker info --format '{{.Driver}}'

This typically reports overlay2 on a modern Linux installation, the generally recommended and most commonly used driver today.

Why the Storage Driver Choice Matters

Different storage drivers have historically had different performance characteristics and limitations, particularly around file copy-up costs and compatibility with specific underlying filesystems — overlay2's broad compatibility and good performance are why it has become the standard default.

docker info --format '{{json .DriverStatus}}'

This reveals additional details about the active storage driver's specific configuration.

Why Changing the Storage Driver Is Rarely Necessary

For the vast majority of standard Linux deployments, the default overlay2 driver is appropriate and performant, with little reason to deviate from it unless facing a very specific, well-understood compatibility requirement that genuinely calls for a different driver.

{
  "storage-driver": "overlay2"
}

This daemon configuration setting reflects the typical, recommended choice for most deployments.

Why Understanding the Storage Driver Matters

While most everyday Docker usage doesn't require directly interacting with storage driver configuration, recognizing that this underlying component is what actually implements the layered filesystem behavior — including copy-on-write and copy-up operations — provides useful context for understanding the storage-related behaviors and performance characteristics observed when working with containers.