Prevent virsh live migration from copy zero -- increment copy on live migration possible ?

[Oliver Dzombic]

Hi,

i am doing a live migration like this:

[root at nodeA ~]#virsh migrate --copy-storage-all --verbose --live kvm1776
qemu+ssh://nodeb/system

which works fine with libvirt version 6.

The zfs backed hdd is 100G, while its thin-provisioned.

The real data on it is 1G.

So even its 1G of data, virsh copies a lot of zero's as it seems.

There is a lot of HDD IO and network activity, but in fact the size at
the target volume does not grow ( since there are no more data ).

After it successfully finished the copy, i tried what will happen with
the --copy-storage-inc parameter:


[root at nodeB ~]# virsh migrate --copy-storage-inc --verbose --live
kvm1776 qemu+ssh://nodea/system

But that didnt change anything. Even both volumes are identical now,
again the whole copy of all ( non existing ) 100GB.

Is there any way to make libvirt just copy real data and not Zero's that
actually do not exist and causing network and HDD IO traffic ?

Thank you !

-- 
Mit freundlichen Gruessen / Best regards

Oliver Dzombic
Layer7 Networks

mailto:info at layer7.net

Anschrift:

Layer7 Networks GmbH
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63571 Gelnhausen

HRB 96293 beim Amtsgericht Hanau
Geschäftsführung: Oliver Dzombic
UST ID: DE259845632