If you need to change the debug log level of the server or components like the SAP adapter, you can do this without having to shutdown the Integration Server but via the Administration UI.

Open a web browser and navigate to the Administration UI. Under the settings section, select the logging option. Select the component you wish to change the debug log level from the dropdown list (this might be the server log or the sap log). Click on the Edit Logging Settings links. Select the new debug log level for the selected component and save changes.

see also How to retrieve the current debug level