cinder-specs/specs/juno/support-volume-backup-for-qcow2.rst
Mike Perez 8ca13afc49 Introduce use case section
This will now require a separate section "Use Cases". This was
originally within "Problem description", but use cases seems to be
missed when it was filled out. This will hopefully improve spec
submission.

Change-Id: I3615ca5ff5c46851e682739a8343242e2f1b0a8d
2015-04-15 22:20:56 -07:00

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================================
Support volume backup for qcow2
================================
https://blueprints.launchpad.net/cinder/+spec/support-volume-backup-for-qcow2
Currently, cinder-backup doesn't support qcow2 format disk. Add the support
for it will make drivers which use qcow2 as volume, such as glusterfs etc,
work together with cinder-backup, and can also make nfs driver use qcow2 as
volume be possible.
Problem description
===================
Currently, cinder-backup doesn't support qcow2 format disk because the backup
code assumes the source volume is a raw volume. The destination (i.e. swift,
rbd) should absolutely remain universal across all volume back-ends.
Use Cases
=========
Proposed change
===============
* Add qemu-nbd support to cinder-backup. Qemu-nbd can mount qcow2 volume as
a raw device to the host
* The backup_volume method in base class of remotefs driver (cinder.volume.
drivers.nfs.RemoteFsDriver:backup_volume) will mount qcow2 volume as nbd
device before call backup_service's backup method
Alternatives
------------
None
Data model impact
-----------------
None
REST API impact
---------------
None
Security impact
---------------
None
Notifications impact
--------------------
None
Other end user impact
---------------------
None
Performance Impact
------------------
None
Other deployer impact
---------------------
Storage node which running cinder-volume will contains nbd kernel module.
Developer impact
----------------
None
Implementation
==============
Assignee(s)
-----------
Primary assignee:
Trump.Zhang <zhangleiqiang@huawei.com>
Work Items
----------
* Add qemu-nbd support to cinder-backup. Qemu-nbd can mount qcow2 volume as
a raw device to the host
* The backup_volume method in base class of remotefs driver (cinder.volume.
drivers.nfs.RemoteFsDriver:backup_volume) will mount qcow2 volume as nbd
device before call backup_service's backup method
Dependencies
============
None
Testing
=======
None
Documentation Impact
====================
None
References
==========
None