- Added volumes documentation

docs/sources/use/working_with_volumes.rst

@@ -0,0 +1,87 @@
+:title: Working with Volumes
+:description: How to create and share volumes
+:keywords: Examples, Usage, volume, docker, documentation, examples
+
+.. _volume_def:
+
+Data Volume
+===========
+
+.. versionadded:: v0.3.0
+   Data volumes have been available since version 1 of the
+   :doc:`../api/docker_remote_api`
+
+A *data volume* is a specially-designated directory within one or more
+containers that bypasses the :ref:`ufs_def` to provide several useful
+features for persistant or shared data:
+
+* **Data volumes can be shared and reused between containers.** This
+  is the feature that makes data volumes so powerful. You can use it
+  for anything from hot database upgrades to custom backup or
+  replication tools. See the example below.
+* **Changes to a data volume are made directly**, without the overhead
+  of a copy-on-write mechanism. This is good for very large files.
+* **Changes to a data volume will not be included at the next commit**
+  because they are not recorded as regular filesystem changes in the
+  top layer of the :ref:`ufs_def`
+
+Each container can have zero or more data volumes.
+
+Getting Started
+...............
+
+
+
+Using data volumes is as simple as adding a new flag: ``-v``. The parameter ``-v`` can be used more than once in order to create more volumes within the new container. The example below shows the instruction to create a container with two new volumes::
+
+  docker run -v /var/volume1 -v /var/volume2 shykes/couchdb
+
+For a Dockerfile, the VOLUME instruction will add one or more new volumes to any container created from the image::
+
+  VOLUME ["/var/volume1", "/var/volume2"]
+
+
+Create a new container using existing volumes from an existing container:
+---------------------------------------------------------------------------
+
+
+The command below creates a new container which is runnning as daemon ``-d`` and with one volume ``/var/lib/couchdb``::
+
+  COUCH1=$(sudo docker run -d -v /var/lib/couchdb shykes/couchdb:2013-05-03)
+
+From the container id of that previous container ``$COUCH1`` it's possible to create new container sharing the same volume using the parameter ``-volumes-from container_id``::
+
+  COUCH2=$(sudo docker run -d -volumes-from $COUCH1 shykes/couchdb:2013-05-03)
+
+Now, the second container has the all the information from the first volume.
+
+
+Create a new container which mounts a host directory into it:
+-------------------------------------------------------------
+
+  -v=[]: Create a bind mount with: [host-dir]:[container-dir]:[rw|ro].
+  If "host-dir" is missing, then docker creates a new volume.
+
+  This is not available for a Dockerfile due the portability and sharing purpose of it. The [host-dir] volumes is something    100% host dependent and will break on any other machine.
+
+For example::
+
+  sudo docker run -v /var/logs:/var/host_logs:ro shykes/couchdb:2013-05-03
+
+The command above mounts the host directory ``/var/logs`` into the container with read only permissions as ``/var/host_logs``.
+
+.. versionadded:: v0.5.0
+
+Volumes & persistent data storage
+=================================
+
+Current status
+..............
+
+Docker has volumes which can be reused from container to container. These volumes have the following limitations:
+
+* they can't be imported and exported (without piping data into and out of the container)
+* they can't be backed up and restored from backups (without piping data into and out of the container)
+* they can't be stored on custom storage (e.g.: use high IOPS storage for a volume and regular IOPS storage for others)
+* it's not possible to cherry pick the volumes to be used from an old container in a new container
+* it's not possible to manage the volumes after deleting the containers to which they were attached