I have been working with a team responsible for a big migration from MOSS 2007 to SharePoint 2013. The team has a migration tool using web service copy.asmx to move files across SharePoint version. None of issues has happened if we directly upload files into SharePoint library via uploading dialog. However, when we use the tool, it throws out the error that the given file exceeds the limit

We followed several basic tips to increase the maximum size supported by changing value in maxRequestLength in the root web.config. I thought that changing registry key in WebClient (WebDav) would get the issue sorted out as well.

We finally realized that adding the following code to the web.config in the path C:Program FilesCommon FilesMicrosoft SharedWeb Server Extensions15ISAPI is one of the walkarounds.

<location path="copy.asmx">
        <httpRuntime maxRequestLength="256000" executionTimeout="3333" />

Increase the value in exceutionTimeout to extend the connection.

This post is just a quick tip in addition to lots of articles helping you to overcome the limitation when you use SharePoint web service to move or upload file into SharePoint.