Hyper V replica speed increase between subnets

Is there a way to increase speed / throttle up the replication between 2 sites on different subnets ?
I have a site 1 running a production environment of 3 Host servers Windows 2012R2 with Hyper V, replicating to site 2 to a backup server also with Windows 2012R2 Hyper V on another subnet through a VPN on a 100Mbit fibre line. My problem is that the replication speed from site 1 to site 2 stays very low, only at around 10Mbit speed from each Host Server totaling about 30Mbit, this despite the 100Mbit fibre line. All servers at both sites have 1GB NICs. If I try to run a replication between hosts within site 1 on the same subnet, the replication speed is at about 700-800Mbit.
Does anyone know how to throttle up the replication speed between the two subnets ?
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Tore JacobsenSystem adminstratorAsked:
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Lee W, MVPTechnology and Business Process AdvisorCommented:
Hyper-V does not try to limit your bandwidth and there's no reason Hyper-V would have a problem over subnets... I would suggest you perform tests on your link between the two sites.  Is there a VPN between them?  Are they connected via different ISPs?  How fast do large files copy over?

If you WANTED to throttle (if someone other than you setup the replication and maybe implemented something) you might be able to adjust it using information in this blog http://www.thomasmaurer.ch/2013/12/throttling-hyper-v-replica-traffic/ to enable PowerShell or Group Policy methods to limit bandwidth with QoS.

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Tore JacobsenSystem adminstratorAuthor Commented:
Hello, there is a VPN between the two sites, the sites have different ISPs, and I have tried a test on the link between the two sites by copying a large file. When I copy a large file from one host at site 1 to the host at site 2, I get a speed of approx 35Mbit, about 3 times as much as when the same host at site 1 is replicating to the host at site 2. This even when there are no other of the other 2 hosts replicating, I still only get approx 10-11Mbit speed from the one host replicating. In other words, about a third of the speed compared to a plain file copy.
The fact that I only get a max of about 35Mbit between the sites, when my fibre line is at 100Mbit is also strange, as when I download a large file from any other external website I may get as much as double that depending on other traffic.
Any ideas why the hosts refuse to send replicas at full capacity even when they have more available speed ?
Philip ElderTechnical Architect - HA/Compute/StorageCommented:
Use WireShark to gauge where the bottleneck is in the setup.

Make sure the VPN gateways are spec'd to handle 100Mbits of throughput with any of the extras also enabled (IPS ETC).
Tore JacobsenSystem adminstratorAuthor Commented:
We fixed the issue by creating a seperate disk for pagefile on all servers. And choosing not to replicate that disk. Now it's alot less data replicating compared to before. Thanks
Philip ElderTechnical Architect - HA/Compute/StorageCommented:
If the page file is changing that much there may be a performance issue there.

Verify the VMs are not paging too often. If they are, not enough RAM has been assigned to the VM for the workloads running therein.
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Windows Server 2012

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