Re: [Qemu-devel] disk image: self-organized format or raw file

[吴兴博]

On Tue, Aug 12, 2014 at 10:07 AM, Eric Blake <address@hidden> wrote:

On 08/12/2014 07:45 AM, 吴兴博 wrote:

[please don't top-post on technical lists]

Sorry about that.. 

> Thanks for your information. It's really helpful.
> I think adding a bitmap alongside the raw file ( or just within that file)

Umm, how do you propose to add a bitmap within a raw file?  The moment
the file contains metadata, it is no longer raw, but some other format.
 You'd need a way to reliably delineate the portion of the file that
contains the bitmap and therefore must not be exposed to the guest.

Yes a agree. It's not raw anymore. It should be some 'lightweight' format.

> would be suffice to distinguish between present or in backing file.
> The idea in FVD looks similar to 'addcow'---use bitmap but delegating
> allocation to FS. However FVD seems to have been ignored by community.

Care to give a pointer to a URL describing the FVD format?

http://lists.nongnu.org/archive/html/qemu-devel/2011-01/msg00398.html

This thread could be the clearest message on FVD.

It also has a paper published on USENIX conference.

https://www.usenix.org/event/atc11/tech/final_files/Tang.pdf

--
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org