Re: [Xen-API] How snapshot work on LVMoISCS SR

[Ian Blenke <ian@xxxxxxxxxx>]

On Tue, Jan 26, 2010 at 5:18 PM, Daniel Stodden
<daniel.stodden@xxxxxxxxxx> wrote:
> On Tue, 2010-01-26 at 17:07 -0500, Anthony Xu wrote:
>> The other thing I'd like to do is how XCP handle disk cache inside VM
>> when creating a snapshot? I saw from Xencenter seem the VM is stopped
>> temporarily when creating a snapshot.
>>
>> Does VM flush dirty disk cache when creating snapshot?
>
> Depends what you mean by disk caches. All I/O performed by the backend
> non-buffered, so there's presently no need to flush. As soon as a guest
> I/O request is processed, it essentially goes directly to the disk.

If you're asking whether the VM is advised to quiesce its filesystem
by the frontend driver device being snapshotted on the backing store,
I believe the answer to that question is "no".

Please correct me if I'm wrong.

- Ian Blenke <ian@xxxxxxxxxx>

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