On Fri, 03/13 17:01, Wen Congyang wrote: > On 03/11/2015 02:49 PM, Fam Zheng wrote: > > 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. > > Can the job stream move the data? I don't find the write ops in > block/stream.c.
It is bdrv_co_copy_on_readv that moves data. Fam