doc: Added preliminary rbd and ko info.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>

doc/index.rst

@@ -21,6 +21,7 @@ cluster to ensure that the storage hosts are running smoothly.
    install/index
    config-cluster/index
    init/index
+   rbd/rbd
    ops/index
    rec/index
    config

doc/rbd/rados-rbd-cmds.rst

@@ -0,0 +1,113 @@
+====================
+ RADOS RDB Commands
+====================
+The ``rbd`` command enables you to create, list, introspect and remove block
+device images. You can also use it to clone images, create snapshots,
+rollback an image to a snapshot, view a snapshot, etc. For details on using
+the ``rbd`` command, see `RBD – Manage RADOS Block Device (RBD) Images`_ for
+details. 
+
+
+Creating a Block Device Image
+-----------------------------
+Before you can add a block device to a Ceph client, you must create an image for
+it in the OSD cluster first. To create a block device image, execute the 
+following::
+
+	rbd create {image-name} --size {megabytes} --dest-pool {pool-name}
+	
+For example, to create a 1GB image named ``foo`` that stores information in a 
+pool named ``swimmingpool``, execute the following::
+
+	rbd create foo --size 1024
+	rbd create bar	--size 1024 --pool swimmingpool
+
+.. note:: You must create a pool first before you can specify it as a 
+   source. See `Storage Pools`_ for details.
+
+Listing Block Device Images
+---------------------------
+To list block devices in the ``rbd`` pool, execute the following:: 
+
+	rbd ls
+
+To list block devices in a particular pool, execute the following,
+but replace ``{poolname}`` with the name of the pool:: 
+
+	rbd ls {poolname}
+	
+For example::
+
+	rbd ls swimmingpool
+	
+Retrieving Image Information
+----------------------------
+To retrieve information from a particular image, execute the following,
+but replace ``{image-name}`` with the name for the image:: 
+
+	rbd --image {image-name} info
+	
+For example::
+
+	rbd --image foo info
+	
+To retrieve information from an image within a pool, execute the following,
+but replace ``{image-name}`` with the name of the image and replace ``{pool-name}``
+with the name of the pool:: 
+
+	rbd --image {image-name} -p {pool-name} info
+
+For example:: 
+
+	rbd --image bar -p swimmingpool info	
+
+Resizing a Block Device Image
+-----------------------------
+RBD images are thin provisioned. They don't actually use any physical storage 
+until you begin saving data to them. However, they do have a maximum capacity 
+that you set with the ``--size`` option. If you want to increase (or decrease)
+the maximum size of a RADOS block device image, execute the following:: 
+
+	rbd resize --image foo --size 2048
+
+
+Removing a Block Device Image
+-----------------------------
+To remove a block device, execute the following, but replace ``{image-name}``
+with the name of the image you want to remove:: 
+
+	rbd rm {image-name}
+	
+For example:: 
+
+	rbd rm foo
+	
+To remove a block device from a pool, execute the following, but replace 
+``{image-name}`` with the name of the image to remove and replace 
+``{pool-name}`` with the name of the pool:: 
+
+	rbd rm {image-name} -p {pool-name}
+	
+For example:: 
+
+	rbd rm bar -p swimmingpool
+
+
+Snapshotting Block Device Images
+--------------------------------
+One of the advanced features of RADOS block devices is that you can create 
+snapshots of the images to retain a history of an image's state. Ceph supports
+RBD snapshots from the ``rbd`` command, from a kernel object, from a 
+KVM, and from cloud solutions. Once you create snapshots of an image, you 
+can rollback to a snapshot, list snapshots, remove snapshots and purge 
+the snapshots.
+
+.. important:: Generally, you should stop i/o before snapshotting an image.
+   If the image contains a filesystem, the filesystem should be in a
+   consistent state before snapshotting too.
+
+ 
+
+
+.. _Storage Pools: ../../config-cluster/pools
+.. _RBD – Manage RADOS Block Device (RBD) Images: ../../man/8/rbd/

doc/rbd/rbd-ko.rst

@@ -0,0 +1,73 @@
+==============================
+ RBD Kernel Object Operations
+==============================
+
+Add a Block Device
+------------------
+To add an RBD image as a kernel object, first load the Ceph RBD module:: 
+
+	modprobe rbd
+
+Map the RBD image to the kernel object with ``add``, specifying the IP address 
+of the monitor, the user name, and the RBD image name as follows:: 
+
+	echo "{mon-ip-address}  name={user-name} rbd {image-name}" | sudo tee /sys/bus/rbd/add
+	
+For example:: 
+
+	echo "10.20.30.40  name=admin rbd foo" | sudo tee /sys/bus/rbd/add	
+	
+If you use ``cephx`` authentication, you must also specify a secret. ::
+
+	echo "10.20.30.40  name=admin,secret=/path/to/secret rbd foo" | sudo tee /sys/bus/rbd/add
+
+
+A kernel block device resides under the ``/sys/bus/rbd/devices`` directory and
+provides the following functions: 
+
++------------------+------------------------------------------------------------+
+| Function         | Description                                                |
++==================+============================================================+
+| ``client_id``    | Returns the client ID of the given device ID.              |
++------------------+------------------------------------------------------------+
+| ``create_snap``  | Creates a snap from a snap name and a device ID.           |
++------------------+------------------------------------------------------------+
+| ``current_snap`` | Returns the most recent snap for the given device ID.      |
++------------------+------------------------------------------------------------+
+| ``major``        |                                                            |
++------------------+------------------------------------------------------------+
+| ``name``         | Returns the RBD image name of the device ID.               |
++------------------+------------------------------------------------------------+
+| ``pool``         | Returns the pool source of the device ID.                  |
++------------------+------------------------------------------------------------+
+| ``refresh``      | Refreshes the given device with the SDs.                   |
++------------------+------------------------------------------------------------+
+| ``size``         | Returns the size of the device.                            |
++------------------+------------------------------------------------------------+
+| ``uevent``       |                                                            |
++------------------+------------------------------------------------------------+
+
+
+List Block Devices
+------------------
+Images are mounted as devices sequentially starting from ``0``. To list the 
+devices mounted, execute the following:: 
+
+	ls /sys/bus/rbd/devices	
+
+
+Removing a Block Device
+-----------------------	
+To remove an RBD image, specify its index and use ``tee`` to call ``remove`` as
+follows, but replace ``{device-number}`` with the number of the device you want
+to remove:: 
+
+	echo {device-number} | sudo tee /sys/bus/rbd/remove	
+
+
+Creating a Snapshot
+-------------------
+To create a snapshot of a device, you must specify the device number. ::
+
+	echo sn1 | sudo tee /sys/bus/rbd/devices/0{device-number}/create_snap
+	

doc/rbd/rbd.rst

@@ -0,0 +1,31 @@
+===============
+ Block Devices
+===============
+
+A block is a sequence of bytes (for example, a 512-byte block of data). 
+Block-based storage interfaces are the most common way to store data with 
+rotating media such as hard disks, CDs, floppy disks, and even traditional 
+9-track tape. The ubiquity  of block device interfaces makes a virtual block 
+device an ideal candidate to interact with a mass data storage system like Ceph.
+
+Ceph's RADOS Block Devices (RBD) interact with RADOS OSDs using the 
+``librados`` and ``librbd`` libraries. RBDs are thin-provisioned, resizable 
+and store data striped over multiple OSDs in a Ceph cluster. RBDs inherit
+``librados`` capabilities such as snapshotting and cloning. Ceph's RBDs deliver 
+high performance with infinite scalability to kernel objects, kernel virtual 
+machines and cloud-based computing systems like OpenStack and CloudStack.
+
+The ``librbd`` library converts data blocks into objects for storage in
+RADOS OSD clusters--the same storage system for ``librados`` object stores and 
+the Ceph FS filesystem. You can use the same cluster to operate object stores, 
+the Ceph FS filesystem, and RADOS block devices simultaneously.
+
+.. toctree::
+	:maxdepth: 1
+
+	RADOS Commands <rados-rbd-cmds>
+	Kernel Objects <rbd-ko>
+	
+	
+	
+