Re: [Qemu-devel] question about live migration with storage

[Paolo Bonzini]

On 14/01/2015 03:41, Zhang Haoyu wrote:
> Hi, Paolo,
> what's advantages of drive_mirror over traditional mechanism implemented in 
> block-migration.c ?
> Why libvirt use drive_mirror instead of traditional iterative mechanism as 
> the default way
> of live migration with non-shared storage?

1) Being able to choose which block devices are migrated, and whether
they are migrated incrementally or not.

2) Finer-grain control the parameters of block migration (dirty bitmap
granularity).

3) Block and RAM migration do not share the same socket and thus can
more easily be parallelized.

Note that 1-2 are not yet supported by libvirt as far as I remember.

Paolo