Re: [Qemu-devel] [RFC PATCH 01/14] docs: block replication's description

[Fam Zheng]

On Wed, 03/11 14:44, Wen Congyang wrote:
> On 03/03/2015 03:59 PM, Fam Zheng wrote:
> > On Tue, 03/03 15:53, Wen Congyang wrote:
> >> I test qcow2_make_empty()'s performance. The result shows that it may
> >> take about 100ms(normal sata disk). It is not acceptable for COLO. So
> >> I think disk buff is necessary(just use it to replace qcow2).
> > 
> > Why not tmpfs or ramdisk?
> 
> Another problem:
> After failover, secondary write request will be written in (active disk)?
> It is better to write request to (nbd target). Is there any feature can
> be reused to implement it?

You can use block commit or stream to move the data.

Fam