Hi, Duncan: Thanks for your advice. About the "summit session" you mentioned, what things can I do for it ?
---------- zhangleiqiang (Trump) Best Regards > -----Original Message----- > From: Duncan Thomas [mailto:duncan.tho...@gmail.com] > Sent: Friday, March 28, 2014 12:43 AM > To: OpenStack Development Mailing List (not for usage questions) > Subject: Re: [openstack-dev] [nova] Feature about QEMU Assisted > online-extend volume > > It sounds like a useful feature, and there are a growing number of touch > points > for libvirt assisted cinder features. A summit session to discuss how that > interface should work (hopefully get a few nova folks there as well, the > interface has two ends) might be a good idea > > On 27 March 2014 16:15, Trump.Zhang <zhangleiqi...@gmail.com> wrote: > > Online-extend volume feature aims to extend a cinder volume which is > > in-use, and make the corresponding disk in instance extend without > > stop the instance. > > > > > > The background is that, John Griffith has proposed a BP ([1]) aimed to > > provide an cinder extension to enable extend of in-use/attached volumes. > > After discussing with Paul Marshall, the assignee of this BP, he only > > focus on OpenVZ driver currently, so I want to take the work of > > libvirt/qemu based on his current work. > > > > A volume can be extended or not is determined by Cinder. However, if > > we want the capacity of corresponding disk in instance extends, Nova > > must be involved. > > > > Libvirt provides "block_resize" interface for this situation. For > > QEMU, the internal workflow for block_resize as follows: > > > > 1) Drain all IO of this disk from instance > > 2) If the backend of disk is a normal file, such as raw, qcow2, etc, > > qemu will do the *extend* work > > 3) If the backend of disk is block device, qemu will first judge if > > there is enough free space on the device, if only so, it will do the > > *extend* > work. > > > > So I think the "online-extend" volume will need QEMU Assisted, which > > is simlar to BP [2]. > > > > Do you think we should introduce this feature? > > > > [1] > > https://blueprints.launchpad.net/cinder/+spec/inuse-extend-volume-exte > > nsion [2] > > https://blueprints.launchpad.net/nova/+spec/qemu-assisted-snapshots > > > > _______________________________________________ > > OpenStack-dev mailing list > > OpenStack-dev@lists.openstack.org > > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > > > > > -- > Duncan Thomas > > _______________________________________________ > OpenStack-dev mailing list > OpenStack-dev@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev