Hi Victor, Yes, you are right.
Thanks, Xing ________________________________________ From: Victor Denisov [vdeni...@mirantis.com] Sent: Monday, December 5, 2016 7:13 PM To: OpenStack Development Mailing List (not for usage questions) Cc: Jason Dillaman Subject: Re: [openstack-dev] [cinder] consistency groups in ceph I just realized that probably we create images from individual snapshots of that consistency group and add those images to the new consistency group. Am I correct? On Mon, Dec 5, 2016 at 3:20 PM, Victor Denisov <vdeni...@mirantis.com> wrote: > Or probably when we clone a consistency group from a snapshot we > should clone all the images in this consistency group? > > On Mon, Dec 5, 2016 at 3:15 PM, Victor Denisov <vdeni...@mirantis.com> wrote: >> Hi Xing, >> >> One more question. You mentioned that there is an operation: create >> consistency group from a snap shot. >> Does it mean that an image can be a member of several consistency groups? >> >> Thanks, >> V. >> >> On Tue, Nov 8, 2016 at 6:21 AM, yang, xing <xing.y...@dell.com> wrote: >>> You cannot remove a volume completely if there is still a group snapshot. >>> You can remove the volume from the group but you can’t delete the volume >>> because it still has snapshot dependent on it. So if you want to >>> completely remove a volume that is in a group, you can delete the group >>> snapshot first which will delete the individual snapshot. After that you >>> can remove the volume from the group and delete the volume. >>> >>> More comments inline below. >>> >>> Thanks, >>> Xing >>> >>> >>> ________________________________________ >>> From: Victor Denisov [vdeni...@mirantis.com] >>> Sent: Tuesday, November 8, 2016 12:04 AM >>> To: OpenStack Development Mailing List (not for usage questions) >>> Cc: Jason Dillaman >>> Subject: Re: [openstack-dev] [cinder] consistency groups in ceph >>> >>> One more question. What is the expected behavior if you remove a >>> volume completely? >>> [Xing] You cannot remove the volume completely (delete volume won't >>> succeed) if there is still a group snapshot. >>> >>> Should the group snapshot removed first? Should the volume snapshot be >>> removed from the group snapshot? >>> [Xing] Yes, you should delete the group snapshot first and that will delete >>> the volume snapshot as well. >>> >>> Should we keep the snapshot even if the image doesn't exist anymore? >>> [Xing] You cannot delete the image (volume) if there is still a snapshot. >>> >>> Thanks, >>> Victor. >>> >>> On Tue, Nov 1, 2016 at 7:02 AM, yang, xing <xing.y...@dell.com> wrote: >>>> Hi Victor, >>>> >>>> Please see my answers inline below. >>>> >>>> In Newton, we added support for Generic Volume Groups. See doc below. >>>> CGs will be migrated to Generic Volume Groups gradually. Drivers should >>>> not implement CGs any more. Instead, it can add CG support using Generic >>>> Volume Group interfaces. I'm working on a dev doc to explain how to do >>>> this and will send an email to the mailing list when I'm done. The >>>> Generic Volume Group interface is very similar to CG interface, except >>>> that the Generic Volume Group requires an additional Group Type parameter >>>> to be created. Using Group Type, CG can be a special type of Generic >>>> Volume Group. Please feel free to grab me on Cinder IRC if you have any >>>> questions. My IRC handle is xyang or xyang1. >>>> >>>> http://docs.openstack.org/admin-guide/blockstorage-groups.html >>>> >>>> Thanks, >>>> Xing >>>> >>>> >>>> ________________________________________ >>>> From: Victor Denisov [vdeni...@mirantis.com] >>>> Sent: Monday, October 31, 2016 11:29 PM >>>> To: openstack-dev@lists.openstack.org >>>> Cc: Jason Dillaman >>>> Subject: [openstack-dev] [cinder] consistency groups in ceph >>>> >>>> Hi, >>>> >>>> I'm working on consistency groups feature in ceph. >>>> My question is about what kind of behavior does cinder expect from >>>> storage backends. >>>> I'm particularly interested in what happens to consistency groups >>>> snapshots when I remove an image from the group: >>>> >>>> Let's imagine I have a consistency group called CG. I have images in >>>> the consistency group: >>>> Im1, Im2, Im3, Im4. >>>> Let's imagine we have snapshots of this consistency group: >>>> >>>> CGSnap1 >>>> CGSnap2 >>>> CGSnap3 >>>> >>>> Snapshots of individual images in a consistency group snapshot I will call >>>> CGSnap2Im1 - Snapshot of image 1 from consistency group snapshot 2. >>>> >>>> Qustion 1: >>>> If consistency group CG has 4 images: Im1, Im2, Im3, Im4. >>>> Can CGSnap1 have more images than it already has: Im1, Im2, Im3, Im4, Im5. >>>> >>>> Can CGSnap1 have less images than it already has: Im1, Im2, Im3. >>>> >>>> [Xing] Once a snapshot is taken from a CG, it can no longer be changed. >>>> It is a point-in-time copy. CGSnap1 cannot be modified. >>>> >>>> Question 2: >>>> If we remove image2 from the consistency group. Does it mean that >>>> snapshots of this image should be removed from all the CGSnaps. >>>> >>>> Example: >>>> We are removing Im2. >>>> CGSnaps look like this: >>>> >>>> CGSnap1 - CGSnap1Im1, CGSnap1Im2, CGSnap1Im3 >>>> CGSnap2 - CGSnap2Im1, CGSnap2Im2, CGSnap2Im3, CGSnap3Im4 >>>> CGSnap3 - CGSnap3Im1, CGSnap3Im2, CGSnap3Im3, CGSnap3Im4 >>>> >>>> What happens to snapshots: CGSnap1Im2,CGSnap2Im2, CGSnap3Im2? Do we >>>> remove them, do we keep them. Is it important what we do to them at >>>> all? >>>> >>>> [Xing] If your CG contains 4 volumes when you take the snapshot of the CG, >>>> the resulting CGSnap should be associated with 4 snapshots corresponding >>>> to the 4 volumes. If you add more volumes to the CG or remove volumes >>>> from CG after CGSnap was taken, it should not affect CGSnap. It will only >>>> affect CG snapshots that you take in the future. >>>> >>>> Thanks, >>>> Victor. >>>> >>>> __________________________________________________________________________ >>>> OpenStack Development Mailing List (not for usage questions) >>>> Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe >>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>>> __________________________________________________________________________ >>>> OpenStack Development Mailing List (not for usage questions) >>>> Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe >>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>> >>> __________________________________________________________________________ >>> OpenStack Development Mailing List (not for usage questions) >>> Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe >>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>> __________________________________________________________________________ >>> OpenStack Development Mailing List (not for usage questions) >>> Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe >>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
