Docker Devicemapper takes up too much space solution

All mirrors and cached resources for Docker are stored in the Devicemapper directory, which can cause this directory to consume a lot of disk and even deplete all of the server's hard drives. As shown in the following illustration:


Solution 1: The failure problem is mainly due to the excessive space allocated, using "Docker info" to view:
First back up the required containers and mirrors, using "Docker save" or "Docker export". then suspend Docker; Delete/var/lib/docker directory, rebuild directory, space allocation mkdir-p/var/lib/docker/devicemapper/devicemapper
DD if =/dev/zero of =/var/lib/docker/devicemapper/devicemapper/data bs = 1M count = 0 seek = 8192


The maximum number of files created is 1M * 8192 = 8G Restart Docker .... Setup failed, no language.
Solution 2: Successfully stop Docker!!! This step is critical, otherwise the following settings will fail. Edit the following file: Vim/lib/systemd/system/docker.service
The original contents are as follows: Execstart=/usr/bin/dockerd-current \           -- Add-runtime docker-runc=/usr/libexec/docker/docker-runc-current \            --default-runtime=docker-runc \           -- Exec-opt native.cgroupdriver=systemd \           -- Userland-proxy-path=/usr/libexec/docker/docker-proxy-current \             $OPTIONS            $DOCKER _storage_options \            $DOCKER _network_options             $ADD _registry            $BLOCK _registry            $INSECURE _registry\             $REGISTRIES

Then modify it to the following: Execstart=/usr/bin/dockerd-current \           -- Add-runtime docker-runc=/usr/libexec/docker/docker-runc-current \            --default-runtime=docker-runc \           -- Exec-opt native.cgroupdriver=systemd \           -- Userland-proxy-path=/usr/libexec/docker/docker-proxy-current \            --storage-opt dm.loopdatasize=8g \           -- Storage-opt dm.loopmetadatasize=4g \           --storage-opt dm.basesize=8g \            $OPTIONS             $DOCKER _storage_options             $DOCKer_network_options \            $ADD _registry \             $BLOCK _registry             $INSECURE _registry\            $REGISTRIES

That is, add the following 3 lines:--storage-opt dm.loopdatasize=8g \--storage-opt dm.loopmetadatasize=4g \--stora Ge-opt dm.basesize=8g \
Set the Devicemapper data to 8g,metadata 4G, and the mirror size cannot be greater than 8G.
Delete the original Docker and use the DD command to allocate space Rm-rf/var/lib/docker mkdir-p/VAR/LIB/DOCKER/DEVICEMAPPER/DEVICEMAPPER/DD if =/dev/zero of =/var/lib/docker/devicemapper/devicemapper/data bs= 1 M count= 0 seek= 8192 dd if =/dev/zero of=/var/lib/docker/devi Cemapper/devicemapper/metadata bs= 1 M count= 0 seek= 4096
After completing the steps above Systemctl daemon-reload systemctl start Docker Docker info