7.4 Replication

Problems or Messages


Workload issue requires user intervention

Replication is in recoverable error during replication either during Scheduling Taking Snapshot of Virtual Machine or Scheduling Reverting Virtual Machine to Snapshot before Starting.

This problem occurs when the server is under load and things are taking longer than expected.

The solution is to wait until the replication is complete.

All workloads go into recoverable errors because you are out of disk space.

Verify the free space. If more space is required, remove a workload.

Slow network speeds under 1 MB.

Confirm that the source machine’s Network Interface Card’s duplex setting is on and the switch is connected to matches (i.e. if the switch is set to auto, the source can’t be set to 100 MB. They need to match.)

Slow network speeds over 1 MB.

Measure the latency by running the following from the source to the Forge:

ping forge_ip –t

Allow it to run for 50 iterations and the average will indicate the latency.

Also see Optimizing File-based Transfers for WAN Connections.

:”The file transfer cannot begin - port 3725 is already in use”


“3725 unable to connect”

Ensure that the port is open and listening:

Run netstat -ano on the workload.

Check the firewall.

Retry the replication.

“Controller connection not established.”

Replication fails at the Take Control of Virtual Machine step.

This error occurs when the replication networking information is invalid. Either the DHCP server is not available or the replication virtual network is not routable to the Forge Management VM.

Change the replication IP to a static IP or enable the DHCP server.

Ensure the virtual network selected for replication is routable to the Forge Management VM.

Replication job does not start (stuck at 0%)

“Controller connection not established.”

This error can occur for different reasons and each has a unique solution:

  • For environments using a local proxy with authentication, bypass the proxy or add proper permissions to resolve this problem. See knowledgebase article Q20339 for more details.

  • If local or domain policies restrict required permissions, to resolve this problem follow the steps outlined in knowledgebase article Q20862.

This is a common issue when Forge has been added to a domain and domain policies are applied with restrictions. See Group Policy and User Rights.

7.4.1 Optimizing File-based Transfers for WAN Connections

The following settings will optimize file-based transfers across a Wide Area Network. These settings are global and will affect all replications, including file-based and VSS replications.

To optimize over the network replications, you need to modify the productinternal.config file in the \Program Files\PlateSpin Portability Suite Server\Web folder.

NOTE:Local gigabit LAN replication speeds may be negatively impacted if these values are modified.

Below is a list of the configuration parameters with two sets of values: the defaults and the values recommended for optimum operation in a high-latency WAN environment.

Table 7-2 Default and Optimized Configuration Parameters


Default Value

Optimized Value


Controls the number of TCP connections opened for file-based data transfer.


4 to 6


Specifies the packet-level compression threshold in bytes.

0 (disabled)

max 65536 (64 KB)


Controls the number of threads used for packet-level data compression. This is ignored if compression is disabled. Since the compression is CPU-bound, this setting might have a performance impact.




TCP/IP window size setting for file transfer connections. It controls the number of bytes sent without TCP acknowledgement, in bytes.

When the value is set to 0, the default TCP window size is used (8 KB). For custom sizes, specify the size in bytes. Use the following formula to determine the proper value:


For example, for a 100 Mbps link with 10 ms latency, the proper buffer size would be:

(100/8)*0.01*1024*1024 = 131072 bytes

0 (8192 bytes)

max 5242880 (5 MB)