[Qemu-devel] Stalls on Live Migration of VMs with a lot of memory

[Peter Lieven]

Hi all,

is there any known issue when migrating VMs with a lot of (e.g. 32GB) 
of memory.
It seems that there is some portion in the migration code which takes 
too much time when the number
of memory pages is large.

Symptoms are: Irresponsive VNC connection, VM stalls and also 
irresponsive QEMU Monitor (via TCP).

The problem seems to be worse on 10G connections between 2 Nodes (i 
already tried limiting the
bandwidth with the migrate_set_speed command) than on 1G connections.

The problem also seems to be worse in qemu-kvm-1.0 than in 
qemu-kvm-0.12.5.

Any hints?

Thanks,
Peter