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Date: Thu, 09 Jul 2009 16:06:18 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 3/3] add live dumping capability
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: qemu-devel@nongnu.org

>> With the previous cleanups in place, it is easy to trigger
>> restart when the state machine goes from the COMPLETING to the
>> COMPLETED state. Besides this, the patch is just simple
>> scaffolding for the monitor command and to migrate to a file
>> rather than a pipe (which is a bit simpler because we do not
>> need non-blocking I/O).
>
> Then this isn't live migration.

Sorry, I cannot understand this remark.

> This is functionally equivalent to migrate "exec:dd of=filename", no?

Yes, except for restarting at the end.

> If you were truly dumping an actual core file and things remained
> "live", that would be compelling, but it would be a lot easier to just
> implement that as an external process. If you just used a table that
> mapped section names and versions to length, you only really need to
> understand the format of ram and cpu save sections.

I already have the code to read ram and cpu save sections.  I don't need 
the "core file" to be ELF; I just need the live state to be dumped with 
as small downtime as possible, and the live migration support provides that.

Paolo