What does Docker run --storage-opt size=XYZ means?

Question

Docker run cli command has an option --storage-opt used like this:

docker run --storage-opt size=XYZ ....nginx

Does the "XYZ" size specified above refer to the CoW layer or the total size of base image and CoW layer as discussed in this link ?

Answer 1

From: https://docs.docker.com/engine/reference/commandline/run/#set-storage-driver-options-per-container

docker run -it --storage-opt size=120G fedora /bin/bash

This (size) will allow to set the container rootfs size to 120G at creation time. This option is only available for the devicemapper, btrfs, overlay2, windowsfilter and zfs graph drivers. For the devicemapper, btrfs, windowsfilter and zfs graph drivers, user cannot pass a size less than the Default BaseFS Size. For the overlay2 storage driver, the size option is only available if the backing fs is xfs and mounted with the pquota mount option. Under these conditions, user can pass any size less then the backing fs size.