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From "Mice Xia" <>
Subject RE: [MERGE] Support VM Snapshot
Date Wed, 30 Jan 2013 08:54:13 GMT
Adding VM states are likely to have some side-effects, but for moveVMToUser case, does it
explicitly reject other transient states such as stating/stopping/migrating?


-----Original Message-----
From: Murali Reddy [] 
Sent: Wednesday, January 30, 2013 4:10 PM
Subject: Re: [MERGE] Support VM Snapshot

On 30/01/13 1:14 PM, "Mice Xia" <> wrote:

>I havenĀ¹t tested all possible cases, but due to the fact possible VM 
>state transits are defined by state machine, all operations that 
>results in VM state change are blocked (or fail) when VM in 
>snapshotting or reverting state.
>For operations that does not cause VM state change, it depends on the 
>implementation. Let's say if moveVMToUser has no requirement to the 
>state of target VM, and does not check VM state programmatically, it 
>will succeed.

I agree for the operations that need state transition, by virtue of the fact that there won't
be state transition from the new states, operation will be blocked.

For the operations that has logic to perform/reject operation on the state of the VM is Running/Stopped,
I suspect possibility of regressions. In the e.g. moveVMToUser, it blocks the operation if
VM state is Running, but will succeed if the state is 'RunningSnapshotting' which is un-intended.

>-----Original Message-----
>From: Murali Reddy []
>Sent: Wednesday, January 30, 2013 3:12 PM
>Subject: Re: [MERGE] Support VM Snapshot
>>>> Potential impact and notes:
>>>> * 4 new states are added to VM state Machine
>When the VM is in transient states (RunningSnapshotting, 
>StoppedSnapshotting), I see that you have taken care of vmsync. But 
>have you ensured that all the concurrent operations on the VM are 
>blocked when the VM is in RunningSnapshotting, StoppedSnapshotting states? For e.g.
>Can moveVMToUser can simply go ahead if the VM is in 'RunningSnapshotting'
>state but would have failed if VM was in 'Running' sate.?

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