Re: [Qemu-devel] QEMU interfaces for image streaming and post-copy block migration

[Kevin Wolf]

Am 07.09.2010 17:09, schrieb Stefan Hajnoczi:
> Right, I'm a little hesitant to get too far into discussing the
> management interface because I remember long threads about polling and
> async.  I never fully read them but I bet some wisdom came out of them
> that applies here.
> 
> There are two ways to do a long running (async?) task:
> 1. Multiple smaller pokes.  Perhaps completion of a single poke is
> async.  But the key is that the interface is incremental and driven by
> the management stack.
> 2. State.  Turn on streaming and watch it go.  You can find out its
> current state using another command which will tell you whether it is
> enabled/disabled and progress.  Use a command to disable it.

I think we need option 2 in any case for users not using libvirt. I for
one wouldn't really love to type in monitor commands every few seconds
to get the streaming done. ;-)

Let's start with this. We can always add option 1 for more sophisticated
cases later if it's desired by users.

Kevin