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      Copyright (c) 2014 EMC Corporation
      All Rights Reserved.

      Licensed under the Apache License, Version 2.0 (the "License"); you may
      not use this file except in compliance with the License. You may obtain
      a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

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      License for the specific language governing permissions and limitations
      under the License.

Unity Driver
============

EMC manila driver framework (EMCShareDriver) utilizes the EMC storage products
to provide the shared filesystems to OpenStack. The EMC manila driver is a
plugin based driver which is designed to use different plugins to manage
different EMC storage products.

Unity plugin is the plugin which manages the Unity Storage System to provide
shared filesystems.  EMC driver framework with Unity plugin is referred to as
Unity driver in this document.

This driver performs the operations on Unity by REST API.  Each backend manages
one Unity Storage System. Multiple manila backends need to be configured to
manage multiple Unity Storage Systems.

Requirements
------------

- Unity OE 4.0.1 or higher.
- StorOps 0.2.17 or higher is installed on Manila node.
- Following licenses are activated on Unity:
  * CIFS/SMB Support
  * Network File System (NFS)
  * Thin Provisioning
  * Fiber Channel (FC)
  * Internet Small Computer System Interface (iSCSI)


Supported Operations
--------------------

In detail, users are allowed to do following operation with EMC Unity
Storage Systems.

* Create/delete a NFS share.
* Create/delete a CIFS share.
* Extend the size of a share.
* Modify the host access privilege of a NFS share.
* Modify the user access privilege of a CIFS share.
* Take/Delete snapshot of a share.
* Create a new share from snapshot.


Supported Network Topologies
----------------------------

flat, VLAN


Pre-Configurations
------------------

On Manila Node
``````````````

StorOps library is required to run Unity driver.
Please install it with the pip command.
You may need root privilege to install python libraries.

::

    pip install storops


Configurations
--------------

Following configurations are introduced for the Unity plugin.

* emc_interface_ports: White list of the ports to be used for connection.
  Wild card character is supported.
  Examples: spa_eth1, spa_*, *
* emc_nas_server_pool: The pool used to persist the meta-data of created
  NAS servers.  Wild card character is supported.
  Examples: pool_1, pool_*, *


API Implementations
-------------------

Following driver features are implemented in the plugin.

* create_share: Create a share and export it based on the protocol used
  (NFS or CIFS).
* create_share_from_snapshot: Create a share from a snapshot - clone a
  snapshot.
* delete_share: Delete a share.
* extend_share: Extend the maximum size of a share.
* create_snapshot: Create a snapshot for the specified share.
* delete_snapshot: Delete the snapshot of the share.
* update_access: recover, add or delete user/host access to a share.
* allow_access: Allow access (read write/read only) of a user to a
  CIFS share.  Allow access (read write/read only) of a host to a NFS
  share.
* deny_access: Remove access (read write/read only) of a user from
  a CIFS share.  Remove access (read write/read only) of a host from a
  NFS share.
* ensure_share: Check whether share exists or not.
* update_share_stats: Retrieve share related statistics from Unity.
* get_network_allocations_number: Returns number of network allocations for
  creating VIFs.
* setup_server: Set up and configures share server with given network
  parameters.
* teardown_server: Tear down the share server.

Restrictions
------------

* EMC Unity does not support the same IP in different VLANs.