title: Is Docker slow when using device mapper on Fedora?
body: <p>I am experimenting docker and I plan to dockerize my project's  CI infratsructure. 
     I am building dockerfiles on 3 different machines: Fedora, Ubuntu, and Boot2Docker (a virtiual machine under windows). </p>
  
  <p>Docker builds on fedora are a lot slower than on the other 2 machines, especially the opration that creates a new image after a Step in the Dockerfile. </p>
  
  <p>So my question is:  Is device mapper a lot slower than AUFS or should I search for some other reason ? Should I expect better if I put in place a RHEL7 config ?    </p>
  
  <p>Config1:  fedora 21  (3.18.3-201.fc21.x86_64) </p>
  
  <pre><code>sudo docker info
  Containers: 27
  Images: 1353
  Storage Driver: devicemapper
  Pool Blocksize: 65.54 kB                                                                                                                                                                                                                    
  Backing Filesystem: extfs                                                                                                                                                                                                                   
  Data Space Used: 82.77 GB                                                                                                                                                                                                                   
  Data Space Total: 107.4 GB                                                                                                                                                                                                                  
  Metadata Space Used: 103.9 MB                                                                                                                                                                                                               
  Metadata Space Total: 2.147 GB                                                                                                                                                                                                              
  Udev Sync Supported: true                                                                                                                                                                                                                   
  Library Version: 1.02.93 (2015-01-30)                                                                                                                                                                                                       
  Execution Driver: native-0.2                                                                                                                                                                                                                 
  Kernel Version: 3.18.3-201.fc21.x86_64                                                                                                                                                                                                       
  Operating System: Fedora 21 (Twenty One)                                                                                                                                                                                                     
  CPUs: 8                                                                                                                                                                                                                                      
  Total Memory: 31.38 GiB                                 
  </code></pre>
  
  <p>Config2: Ubuntu 14.04.2 LTS</p>
  
  <pre><code>Containers: 89
  Images: 589
  Storage Driver: aufs
  Backing Filesystem: extfs
  Dirperm1 Supported: false
  Execution Driver: native-0.2
  Kernel Version: 3.13.0-49-generic
  Operating System: Ubuntu 14.04.2 LTS
  CPUs: 8
  Total Memory: 31.38 GiB
  </code></pre>
  
  <p>Config3: Boot2Docker (virtual linux machine running under Windows. docker default solution for Windows)</p>
  
  <pre><code>docker info
  Containers: 14
  Images: 215
  Storage Driver: aufs
  Backing Filesystem: extfs
  Dirperm1 Supported: true
  Execution Driver: native-0.2
  Kernel Version: 3.18.11-tinycore64
  Operating System: Boot2Docker 1.6.0 (TCL 5.4); master : a270c71 - Thu Apr 
  CPUs: 8
  Total Memory: 1.961 GiB
  </code></pre>
  
  <p>I read <a href="http://developerblog.redhat.com/2014/09/30/overview-storage-scalability-docker/" rel="nofollow">this</a> article but it still did not help me to clear things out. </p>