Re: [Qemu-devel] [PATCH] vmdk: Fix format specific information (create type) for streamOptimized

[Fam Zheng <famz@redhat.com>]

On Thu, 01/23 15:42, Kevin Wolf wrote:
> Am 23.01.2014 um 08:10 hat Fam Zheng geschrieben:
> > Previously the field is wrong:
> > 
> >     $ ./qemu-img create -f vmdk -o subformat=streamOptimized /tmp/a.vmdk 1G
> > 
> >     $ ./qemu-img info /tmp/a.vmdk
> >     image: /tmp/a.vmdk
> >     file format: vmdk
> >     virtual size: 1.0G (1073741824 bytes)
> >     disk size: 12K
> >     Format specific information:
> >         cid: 1390460459
> >         parent cid: 4294967295
> > >>>     create type: monolithicSparse
> >         <snip>
> > 
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> 
> Thanks, applied to the block branch.
> 
> By the way, I tried converting a raw image to streamOptimised and got
> this:
> 
> qemu-img: Could not write to allocated cluster for streamOptimized
> qemu-img: error while writing sector 63: Input/output error
> 
> The problem seems to be that qemu-img tries to be clever and doesn't
> write out sparse parts, which breaks up the first cluster into multiple
> write requests. Adding -S 64 makes it work. Should we change something
> to get a working default?
> 

I think we should make qemu-img even cleverer to not do this with compressed
image like this. It was once in my todo list but I forgot to complete it. I'll
pick it up.

Thanks,

Fam