Re: reliable live migration of large and busy guests

[Olaf Hering <olaf@aepfle.de>]

On Tue, Nov 06, Keir Fraser wrote:

> It's known that if you have a workload that is dirtying lots of pages
> quickly, the final stop-and-copy phase will necessarily be large. A VM that
> is busy dirtying lots of pages can dirty pages much quicker than they can be
> transferred over the LAN.

In my opinion such migration should be done at application level.

> > Should 'xm migrate --live' and 'xl migrate' get something like a
> > --no-suspend option?
> 
> Well, it is not really possible to avoid the suspend altogether, there is
> always going to be some minimal 'dirty working set'. But could provide
> parameters to require the dirty working set to be smaller than X pages
> within Y rounds of dirty page copying.

Should such knobs be exposed to the tools like x[lm] migrate --knob1 val --knob2 val?

Olaf