Cinder/PengyunZettastorDriver

Related blueprints
https://blueprints.launchpad.net/cinder/+spec/pengyun-cinder-driver

Overview
Pengyun Zettastor is a software defined storage product, and a software running in host. the goal is to keep data more safe. Pengyun Zettastor driver interacts with the storage device both in control plane and data plane. Through control plane to send Rest request and Through data plane to transfer data, it can afford more pressure.

The purpose of this blue print is to add Pengyun Zettastor Driver to Cinder.

Benefits of this driver
Adding the Pengyun Zettastor driver will bring the following advantages:
 * Better I/O performance using Zettastor cache feature when there is a SSD in host.
 * Easier Qos control.
 * More stable backend storage.

Cinder
Add new driver in /cinder/volume/drivers path that uses iSCSI interact with Pengyun Zettastor storage., and realize cinder driver minimum features:
 * Volume Create/Delete
 * Volume Attach/Detach
 * Snapshot Create/Delete
 * Create Volume from Snapshot
 * Get Volume Stats
 * Copy Image to Volume
 * Copy Volume to Image
 * Clone Volume
 * Extend Volume