Re: [Qemu-devel] Adding Disk-Level Introspection to QEMU

[Stefan Hajnoczi]

On Tue, Apr 23, 2013 at 7:22 PM, Eric Blake <address@hidden> wrote:
> On 04/23/2013 11:12 AM, Wolfgang Richter wrote:
>> I'm interested in adding introspection of disk writes to QEMU for various
>> applications and research potential.
>>
>> What I mean by introspection of disk writes is that, when enabled, each
>> write
>> passing through QEMU to backing storage would also be copied to an
>> introspection channel for further analysis.
>
> Sounds like you would be benefited by the block-backup series, with an
> NBD server as the point where you inject your introspection.
>
> https://lists.gnu.org/archive/html/qemu-devel/2013-04/msg04629.html
>
> The existing drive-mirror command can also target an NBD destination,
> with similar effects.

One adjustment needs to be made: do not update the backup bitmap.
This allows you to continue "tapping" guest writes even if they
rewrite the same disk sectors.

Stefan