Sorry, Edward. It's been so late. Mails from list growed day by day and I didn't know how to handle it... until today I finally found a perfect way to organise all those mail (ha, using google "Lable" and "Filter") and I found your message.
It has been done, I have added a new API for cinder-api and cinder-volume myself, to roll a volume back to a snapshot. cinder-backup is still in my consideration and I know that "bootable volume" bug too, just don't know there is a patch. But for now I am dispatched to some kind of Load Blancing job (digging in L3 agent and LBaaS agent and some other things), it may be a long while before I come back to Cinder and Ceph things. 2014-01-23 20:52 GMT+08:00 Edward Hope-Morley < edward.hope-mor...@canonical.com>: > Hi Changqian, see comments inline. > > On 02/01/14 07:38, Changqian Zuo wrote: > > Hi, > > > > First time mailing to a list. > > > > I'm trying to add a RBD volume snapshot rollback operation to Cinder. > > I've just got through WSGI part of Cinder API code and have read some > > pieces of Cinder Volume. Now there is not much time for me to complete > > the whole code base (with Ceph driver) very carefully, I need some > > advice. > > > > Is adding a Extension Controller the most suitable way to do this? How > > to deal with snapshot and volume state transformation, would it affect > > other part of Cinder codes? What parts of Cinder codes I should pay > > special attention? > > > > Many thanks. > > > > Some background information: > > > > We're planning to use Cinder bootable volume (Ceph RBD as backend) as > > instance root disk in my company's OpenStack environment. Creating a > > volume snapshot from image, and then use this snapshot to spawn instance > > root volumes. > > > > To backup volume state, I've thought of Cinder-Backup service (still > > need to add a in-use backup for Cinder), but it takes too much space (a > > 80G volume would take at least 248G space for base backup image with x3 > > Ceph replication ratio). The other way is volume snapshot, but in this > > case when restoring volume data, I have to create a new volume from > > snapshot, destroy the original instance (there's no API to change a > > instance's bootable volume), and create a new instance from new volume. > If the you use the ceph backup driver with cinder backup (added > in Havana), it is capable of doing incremental/differential backups > so it only actually stores the data that is in use so e.g. if you have > a 80G volume with 1G of actual data, the backup volume will only be > 1G on disk (x number of replicas). > > You can then do a 'restore' which, again, will only transfer the actual > data. > > Unfortunately, there is a bug in cinder-backup (all drivers) whereby > bootable > volumes cannot be restored, or more specifically volumes cannot be > restored as > bootable. There is currently a patch in progress to resolve this which we > hope will land during the I cycle - > https://review.openstack.org/#/c/51900/ > > hope that helps, > > Ed. > > The old volume can not be removed, for a snapshot is referencing to it > > (the snapshot must be kept). If I do this again and again, there would > > be many snapshots referencing to many different volumes, and I have to > > keep these volumes (not used elsewhere), which is a mess. > > > > > > > > _______________________________________________ > > Mailing list: > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack > > Post to : openstack@lists.openstack.org > > Unsubscribe : > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack > >
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