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Re: [Qemu-devel] Asynchronous / synchronous IO emulation
From: |
Dong, Eddie |
Subject: |
Re: [Qemu-devel] Asynchronous / synchronous IO emulation |
Date: |
Sat, 26 Nov 2016 07:27:44 +0000 |
> > The usage is to construct a secondary hot standby VM (SVM), identical with
> the primary VM (PVM).
> > When an virtual DMA happens in PVM side, we need to know at which
> instruction boundary the virtual DMA is delivered, so that we can replay the
> virtual DMA event at the 2nd VM side, to keep them identical at any time.
> >
> > Asynchronous IO emulations seems to be a little bit more complicate to be
> deterministic...
> > I might be wrong.
>
> There is a record-replay mode that might be worth investigating. See
> docs/replay.txt.
>
> It sounds like you are not using live migration for micro-checkpoints?
> The live migration mechanism would keep memory in sync at each
> checkpoint.
>
> Is this work releated to the COLO effort?
>
> Stefan
Thanks Stefan. COLO is one what we push for high availability.
This is yet another project leveraging KVM for deterministic execution, which
is still in room. I use VM replicating to explain the concept, but it is not
used for high availability.
Eddie