Re: [Qemu-devel] [RFC] block-trace Low Level Command Supporting Disk Introspection

[Wolfgang Richter]

On Tue, May 14, 2013 at 6:04 AM, Paolo Bonzini <address@hidden> wrote:

Il 14/05/2013 10:50, Kevin Wolf ha scritto:

> Or, to translate it into our existing terminology, drive-mirror
> implements a passive mirror, you're proposing an active one (which we
> do want to have).
>
> With an active mirror, we'll want to have another choice: The mirror can
> be synchronous (guest writes only complete after the mirrored write has
> completed) or asynchronous (completion is based only on the original
> image). It should be easy enough to support both once an active mirror
> exists.

Right, I'm waiting for Stefan's block-backup to give me the "right"
hooks for the active mirror.

The bulk phase will always be passive, but an active-asynchronous mirror
has some interesting properties and it makes sense to implement it.

Do you mean you'd model the 'active' mode after 'block-backup,' or actually

call functions provided by 'block-backup'?  If I knew more about what you

had in mind, I wouldn't mind trying to add this 'active' mode to 'drive-mirror'

and test it with my use case.  I want to avoid duplicate work, so if you

want to implement it yourself I can defer this.

--
Wolf