Engine 1.10 migrator
Starting from v1.10 docker uses content-addressable IDs for the images and layers instead of using generated ones. This tool calculates SHA256 checksums for docker layer content, so that they don't need to be recalculated when the daemon starts for the first time.
The migration usually runs on daemon startup but it can be quite slow (usually 100-200MB/s) and daemon will not be able to accept requests during that time. You can run this tool instead while the old daemon is still running and skip checksum calculation on startup.
If you use the default storage path:
docker run --rm -v /var/lib/docker:/var/lib/docker docker/v1.10-migrator
If you use devicemapper storage driver (as reported by the storage driver field in
docker info output), you will need to add
--privileged to give the tool access to your storage devices.
See this wiki page for additional information.