Increase the request limit to handle large files – VertiGIS

Overview:

By default, Essentials will refuse to handle any request that exceeds 20MB in size. This can be a conservative value for clients who regularly deal with large volumes of data.

Solution:

Note: Increasing the request limit can have adverse affects. For example, the HTML5 viewer's 'Upload Data' tool will warn users if the number of features in an uploaded file is excessively high. But >20MB spatial files that are complex in other ways may fail to upload without a meaningful error message, or cause issues for the browser once the data is uploaded. Consider advising users of these risks when the request limit is increased past the default.

To increase this limit, modify two settings in the web.config. file: the maximum allowed content length for security filtering, and the maximum request length for the HTTP Runtime.
The <requestLimits> tag within <system.webServer> sets the maximum allowed content length. This value is in bytes.:

<security>
      <requestFiltering>
        <requestLimits maxAllowedContentLength="20971520" />
      </requestFiltering>
    </security>

The <httpRuntime> tag found within the <system.web> tag sets the maximum request length. This value is in kilobytes:

<httpRuntime maxRequestLength="20480" requestValidationMode="2.0" enableVersionHeader="false" />

The maximum you may use here is 4194303. That's 4 gigabytes. We recommend something closer to the default of 20480 (20Mb).

A maximum setting of 20Mb does not necessarily mean a 20Mb file will be permitted, this is due to file encoding which can take up as much as 33%. You will need to adjust the setting accordingly.