We have a lot of virtual machines and I recently tried out the migrate feature of libvirt.

It works like a charm, even without shared storage, but when we try to migrate a VM under a little pressure (a HTTP server gets some 1-5 requests/sec) the migration process hangs at 99%.

After we stop the stressing of the VM, the migration immediately finishes.

I'm using the following command to migrate:

virsh migrate --live --persistent --undefinesource --copy-storage-all --verbose --desturi qemu+ssh://root@DESTINATION/system VM-NAME

Do you have any advice on this?