----- Original Message ----- > From: "Michael Pasternak" <[email protected]> > To: "Livnat Peer" <[email protected]> > Cc: "engine-devel" <[email protected]> > Sent: Monday, May 28, 2012 2:37:10 PM > Subject: Re: [Engine-devel] Adding atomic restore snapshot command at backend > > > Hi Livnat, > > On 05/28/2012 02:07 PM, Livnat Peer wrote: > > On 28/05/12 12:59, Michael Pasternak wrote: > >> > >> Currently 'restore snapshot' done in two steps on a client side: > >> > >> 1. TryBackToAllSnapshotsOfVm > >> 2. RestoreAllSnapshots > >> > >> This implementation creates race condition on 1 and therefore > >> unstable & bug prone,
IIRC, there is an easy way to fix this, by polling on engine jobs and not vdsm tasks, no? > >> i suggested refactoring 2 to include 1 as single atomic operation > >> at backend. > >> > >> > > > > Hi Michael, > > > > The two commands above are used for functionality that is needed > > regardless of the functionality you are looking for. > > We want to present the user the option to preview a snapshot > > without > > committing to it and without loosing the current snapshot. > > I think we need to model the the two options above in the REST, it > > is > > functionality that is used in the UI. +1 for that. > > this is out of scope of this RFE. > > > > > What you are looking for is a functionality 'restore to snapshot', > > this > > functionality does not exist in the engine in a single step, and I > > think > > that because we assumed that the user can get it in two steps It > > wasn't > > prioritize so far. > > the cons. of this approach is an async nature of the former command. > > > > > Implementing the missing functionality with the two functions above > > is > > a compromise that was done in the API. > > > > To summarize I think the requirement you present is a missing > > functionality in the engine and solving it is not about refactoring > > the > > two existing verbs into one. > > what i meant is not deprecating/refactoring old commands, but > introducing > new one that reusing them and expose as single (atomic) command > called > 'RestoreAllSnapshots', > > sorry if i wasn't clear. another suggestion is to have a way to send to the engine list of commands that will be performed. > > > > > Thanks, Livnat > > > > > -- > > Michael Pasternak > RedHat, ENG-Virtualization R&D > _______________________________________________ > Engine-devel mailing list > [email protected] > http://lists.ovirt.org/mailman/listinfo/engine-devel > _______________________________________________ Engine-devel mailing list [email protected] http://lists.ovirt.org/mailman/listinfo/engine-devel
