Slow ESXi migration through the tunnel. What to do?

Question

VPN

We have two offices. Each of them has an ESXi 6.5 server, which is managed by the Sphere.
All this is united by Mikrotik Tunnels. I tried different options - GRE + routes, included EOIP in the local bridge, even raised VPLS.
As a result, I have the following picture - there is a connection, I measured the speed inside the tunnel, including copying files between VMs (MTU 1500 is installed) - 100+ Mbps, ping - 30-35ms. But when migrating a virtual machine, or backing up via Veeam, the speed is about 5Mbps. At some point, it turned out to see as much as 15Mbps, but it doesn’t rise any higher.
Moreover, if the hosts are connected via a gigabit switch, the speed is more than adequate.
I tried to lower the MTU on the ESXi interface up to 1400 - the picture is the same.
Loading processor on Mikrotik during copying 1-2%

Tell me where to dig?

Answer 1

Look at the speed. For vMotion less than 1 gigabit is not recommended at all