Re: [Qemu-devel] [PATCH v5 8/9] QMP commands changes

[Stefan Hajnoczi]

On Tue, Jan 3, 2012 at 3:34 PM, Orit Wasserman <address@hidden> wrote:
> +        .args_type  = "detach:-d,blk:-b,inc:-i,xbrle:-x,uri:s",
> +        .params     = "[-d] [-b] [-i] [-x] uri",
> +        .help       = "migrate to URI"
> +                      "\n\t -d to not wait for completion"
> +                      "\n\t -b for migration without shared storage with"
> +                      " full copy of disk"
> +                      "\n\t -i for migration without"
> +                      " shared storage with incremental copy of disk"
> +                      " (base image shared between source and destination)"
> +                      "\n\t -x to use XBRLE page delta compression",

It's too bad that this algorithm is user-visible and needs to be
expicitly enabled/disabled.  I think it would be useful in a much
wider range of cases if the trade-offs were understood well enough so
that QEMU can include a threshold or heuristic which chooses the
migration algorithm behind the scenes.

I'm afraid that locking XBRLE behind an explicit option means we're
merging dead code.  What do you think?

Stefan