title: Docker devicemapper storage space
body: <p>Am getting the "no space left on device" error while removing a container.</p>
  
  <pre><code># docker rm orientdb1
  Error response from daemon: Driver devicemapper failed to remove root filesystem ba18ea8014b6024eb738502612130244ff363b433f146102c64eb2eb0f3a321c: devmapper: Error saving transaction metadata: devmapper: Error creating metadata file: open /var/lib/docker/devicemapper/metadata/.tmp636968871: no space left on device
  </code></pre>
  
  <p>Here is a snippet from "df -kh" output.</p>
  
  <pre><code>Filesystem               Size  Used Avail Use% Mounted on
  /dev/mapper/centos-root  3.8T  3.8T   20K 100% /
  </code></pre>
  
  <p>Here is a snippet from "du -ksh " output. Which shows that 3.8TB is used.</p>
  
  <pre><code>3.8T    /var/lib/docker
  </code></pre>
  
  <p>This is the "docker info" output.</p>
  
  <pre><code># docker info
  Containers: 56
   Running: 8
   Paused: 0
   Stopped: 48
  Images: 18
  Server Version: 1.12.0
  Storage Driver: devicemapper
   Pool Name: docker-253:0-1196768-pool
   Pool Blocksize: 65.54 kB
   Base Device Size: 10.74 GB
   Backing Filesystem: xfs
   Data file: /dev/loop0
   Metadata file: /dev/loop1
   Data Space Used: 24.51 GB
   Data Space Total: 107.4 GB
   Data Space Available: 20.48 kB
   Metadata Space Used: 29.18 MB
   Metadata Space Total: 2.147 GB
   Metadata Space Available: 20.48 kB
   Thin Pool Minimum Free Space: 10.74 GB
   Udev Sync Supported: true
   Deferred Removal Enabled: false
   Deferred Deletion Enabled: false
   Deferred Deleted Device Count: 0
   Data loop file: /var/lib/docker/devicemapper/devicemapper/data
   WARNING: Usage of loopback devices is strongly discouraged for 
   production use. Use `--storage-opt dm.thinpooldev` to specify a custom 
   block storage device.
   Metadata loop file: /var/lib/docker/devicemapper/devicemapper/metadata
    Library Version: 1.02.107-RHEL7 (2016-06-09)
  Logging Driver: json-file
  Cgroup Driver: cgroupfs
  Plugins:
   Volume: local
   Network: bridge host overlay null
   Swarm: inactive
   Runtimes: runc
  Default Runtime: runc
  Security Options: seccomp
  Kernel Version: 3.10.0-327.22.2.el7.x86_64
  Operating System: CentOS Linux 7 (Core)
  OSType: linux
  Architecture: x86_64
  CPUs: 12
  Total Memory: 251.7 GiB
  Name: my-host1
  ID: KTTY:PSTQ:YQSP:9KZJ:VSVU:DFUZ:CEMF:DYWQ:CA3I:6KUB:6J2J:D4NG
  Docker Root Dir: /var/lib/docker
  Debug Mode (client): false
  Debug Mode (server): false
  Registry: https://index.docker.io/v1/
  WARNING: bridge-nf-call-ip6tables is disabled
  Insecure Registries:
   127.0.0.0/8
  </code></pre>
  
  <p>Would like to understand how 3.8 TB is accounted for from the following (snippet from "docker info")</p>
  
  <pre><code> Data Space Used: 24.51 GB
   Data Space Total: 107.4 GB
   Data Space Available: 20.48 kB
   Metadata Space Used: 29.18 MB
   Metadata Space Total: 2.147 GB
   Metadata Space Available: 20.48 kB
   Thin Pool Minimum Free Space: 10.74 GB
  </code></pre>
  
  <p>Also how can I clean /var/lib/docker to get some free space.</p>