
If Cinder reports discard=true capability then add discard=unmap to disk config setting on attached volume. To have this actually provide unmap/trim support the instance must have been configured with a controller+bus type that can support it. As of now the only one known not to work is virtio-blk. In the case where we detect a configuration that will not work a warning will be logged, but the attachment will continue with the default behavior. An example of how to get a controller and bus to support this is to set the following Glance properties on an image: hw_scsi_model=virtio-scsi hw_disk_bus=scsi This feature also has some requirements for the libvirt and qemu versions being used. There is a check to ensure that libvirt is at least 1.0.6 and qemu is at least 1.6.0. If the minimum versions are not met a warning will be logged, but the attachment will continue with the default behavior. Change-Id: Icd2d20bb6906d9106df34a970b3d81b17bc3ec07 Implements: bp cinder-backend-report-discard
OpenStack Nova README
OpenStack Nova provides a cloud computing fabric controller, supporting a wide variety of virtualization technologies, including KVM, Xen, LXC, VMware, and more. In addition to its native API, it includes compatibility with the commonly encountered Amazon EC2 and S3 APIs.
OpenStack Nova is distributed under the terms of the Apache License, Version 2.0. The full terms and conditions of this license are detailed in the LICENSE file.
Nova primarily consists of a set of Python daemons, though it requires and integrates with a number of native system components for databases, messaging and virtualization capabilities.
To keep updated with new developments in the OpenStack project follow @openstack on Twitter.
To learn how to deploy OpenStack Nova, consult the documentation available online at:
For information about the different compute (hypervisor) drivers supported by Nova, read this page on the wiki:
In the unfortunate event that bugs are discovered, they should be reported to the appropriate bug tracker. If you obtained the software from a 3rd party operating system vendor, it is often wise to use their own bug tracker for reporting problems. In all other cases use the master OpenStack bug tracker, available at:
Developers wishing to work on the OpenStack Nova project should always base their work on the latest Nova code, available from the master GIT repository at:
Developers should also join the discussion on the mailing list, at:
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
Any new code must follow the development guidelines detailed in the HACKING.rst file, and pass all unit tests. Further developer focused documentation is available at:
For information on how to contribute to Nova, please see the contents of the CONTRIBUTING.rst file.
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