I'm going to bring the conversation back to this thread since it got somewhat branched out.
One hurdle in implementing this is that it has been brought to my attention that we do not want all snapshots to be revertible. For example, I believe it is not XenServer best practices to simply revert a snapshot (in fact, there is no API for it). Instead, XenServer says you should delete the existing volume, then create a new volume from the snapshot in its place if you really want to revert. However, the general best practice is to create a new volume and attach it to the VM instead of reverting. So, this means we need some system of determining whether a snapshot can be reverted in order to show/hide the snapshot accordingly in the UI. If we don't, then the revert action will always be there, but it will fail unless the snapshot is actually managed by a storage provider who provides reverting functionality. Originally I thought about including some information about whether each volume supports reverting when querying for volumes. However, I now realize that this should really be done at the snapshot level because the volume could migrate around primary storage, leaving snapshots that have been created by different primary storages. Because of this, I think we should introduce a new interface to PrimaryDataStoreDrivers, 'canRevert(Snapshot)' to go along with the exiting 'revertSnapshot(Snapshot)' which would be used when querying for snapshots to determine whether a snapshot can actually be reverted. I see two options with this approach: 1) Always collect this information when querying for snapshots (like I described above) 2) Only load this information when listing actions for a snapshot. I prefer (1) since (2) requires a new API to be exposed and (2) only solves this problem if the end user is using the default CS UI, otherwise providers creating their own UI would have to query the canRevert API in their own UI. Any thoughts or objections to approach #1? -Chris -- Chris Suich chris.su...@netapp.com NetApp Software Engineer Data Center Platforms – Cloud Solutions Citrix, Cisco & Red Hat On Oct 4, 2013, at 6:35 AM, benoit lair <kurushi4...@gmail.com> wrote: > This would be very great !! > > > 2013/10/3 Daan Hoogland <daan.hoogl...@gmail.com> > >> go go go >> >> >> On Wed, Oct 2, 2013 at 5:07 PM, David Ortiz <dpor...@outlook.com> wrote: >> >>> This sounds like a great idea. >>> >>>> From: chiradeep.vit...@citrix.com >>>> To: dev@cloudstack.apache.org >>>> Subject: Re: [PROPOSAL] Revert to VM disk Snapshot >>>> Date: Mon, 30 Sep 2013 21:53:35 +0000 >>>> >>>> +1. >>>> >>>> On 9/30/13 2:31 PM, "SuichII, Christopher" <chris.su...@netapp.com> >>> wrote: >>>> >>>>> The storage subsystem API currently has an interface for >> takeSnapshot() >>>>> and an associated externally facing API for takeSnapshot. There is >> also >>> a >>>>> method on the primary data store interface for revertSnapshot(). >>> However, >>>>> this method is unused. We would like this storage subsystem interface >>>>> method be hooked up to an externally facing API so that we can provide >>>>> true VM disk backup and recovery. >>>>> >>>>> I will work on formalizing a full functional spec but wanted to get >> this >>>>> up for discussion ASAP. >>>>> >>>>> I have created a JIRA ticket: >>>>> https://issues.apache.org/jira/browse/CLOUDSTACK-4771 >>>>> >>>>> Thanks, >>>>> Chris >>>>> -- >>>>> Chris Suich >>>>> chris.su...@netapp.com<mailto:chris.su...@netapp.com> >>>>> NetApp Software Engineer >>>>> Data Center Platforms Cloud Solutions >>>>> Citrix, Cisco & Red Hat >>>>> >>>> >>> >>> >>
