On 03/11/2015 03:04 PM, Fam Zheng wrote: > On Wed, 03/11 15:01, 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. >> >> When doing failover, we can use it to move the data. After failover, >> I need an endless job to move the data. >> > > I see what you mean. After failover, does the nbd server receive more data > (i.e. do you need a buffer to stash data from the other side)? If you commit > (active disk) to (nbd target), all the writes will go to a single image.
After failover(primary host downs), only secondary qemu works, and nbd server doesn't receive any more data. Thanks Wen Congyang > > Fam > > . >
