live storage migration using blockcopy

[Peter Krempa]

On Mon, Mar 16, 2020 at 17:25:50 +0800, Jing-Wei Su wrote:
> Hello,
> 
> I'm seeking the solution to live storage migration using blockcopy.
> Previously, the "virsh undefine" is required before blockcopy.
> https://www.redhat.com/archives/libvirt-users/2015-October/msg00027.html
> 
> QEMU has "block-dirty-bitmap-*" operations now, are there steps for
> the live storage migration using blockcopy without undefine?

You can nowadays use blockcopy without undefine if you use the
--transient-job flag. (If the VM crashes though the job can't be
recovered and must be fully restarted).

> 
> By the way, why's the purpose of "undefine" before blockcopy?
> Thanks.

We could not continue the job. As you've pointed out it can be done now
but it's not implemented. Either declare that you don't care about the
job being irrecoverable if it fails or you'll need to wait until it's
implemented. Unfortunately it's pretty low on my priority list right
now.