I only have one comment: Can we put this snapshot improvement code out of snapshotmanager?
> -----Original Message----- > From: Alena Prokharchyk [mailto:[email protected]] > Sent: Tuesday, October 09, 2012 11:51 AM > To: [email protected] > Subject: FS on cloudStack createSnapshot synchronization improvement > > Hi All, > > I'm planning to introduce some changes to create snapshot behavior for > the > future cloudStack release (the changes will go to asf/master branch). > The > fix is fixing the problem described below: > > "With the current code for snapshots, cloudStack always creates > snapshot > on the host where vm is Running (for vms in Running state) or on the > host > where vm used to run the last time (for vms in Stopped state). As the > createSnapshot commands are not synchronized on the agent side, the > case > when multiple commands are send to the backend at the same time can > lead > to the performance issues on the hypervisor side. At the end there is > a > high possibility that createSnapshot command might time out on the Xen > side. > The solution is to synchronize number of concurrent snapshots per host > basis. The threshold should be configurable as the customer usually > knows > how many snapshots at a time the backend can handle. > While the concurrent snapshots are being processed by the backend, all > subsequent snapshot commands scheduled for execution on the same host, > should wait in the queue" > > > Here is the feature FS available for the review: > > https://cwiki.apache.org/confluence/display/CLOUDSTACK/Snapshot+improve > ment > s+FS > > If you have any comments/suggestions/questions on the implementation, > please let me know. > > > -Alena.
