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

[Wolfgang Richter]

On Wed, May 22, 2013 at 12:11 PM, Paolo Bonzini <address@hidden> wrote:

> Essentially, if you're RWMJ (not me), and you're keeping a full
> mirror, it's clear that the mirror write stream goes to an nbd server,
> but is it possible to attach a reader to that same nbd server and read
> things back (read-only)?

Yes, it can be done with both qemu-nbd and the QEMU nbd server commands.

Then this means, if there was an active mirror (or snapshot being created), it would

be easy to attach an nbd client as a reader to it even as it is being synchronized

(perhaps dangerous?). 

--
Wolf