Re: [Qemu-devel] [PATCH 08/20] mirror: allow customizing the granularity

[Stefan Hajnoczi]

On Wed, Dec 12, 2012 at 02:46:27PM +0100, Paolo Bonzini wrote:
> @@ -962,6 +963,7 @@ Arguments:
>    file/device (NewImageMode, optional, default 'absolute-paths')
>  - "speed": maximum speed of the streaming job, in bytes per second
>    (json-int)
> +- "granularity": granularity of the dirty bitmap (json-int, optional)

"in bytes" would be nice although the text you added below implies this.

>  - "sync": what parts of the disk image should be copied to the destination;
>    possibilities include "full" for all the disk, "top" for only the sectors
>    allocated in the topmost image, or "none" to only replicate new I/O
> @@ -971,6 +973,10 @@ Arguments:
>  - "on-target-error": the action to take on an error on the target
>    (BlockdevOnError, default 'report')
>  
> +The default value of the granularity is, if the image format defines
> +a cluster size, the cluster size or 4096, whichever is larger.  If it
> +does not define a cluster size, the default value of the granularity
> +is 65536.