3515945 - XS Controller service fails to start

• xs controller is not coming up and fails with:
  com.sap.xs2rt.controller.ControllerExceptions$ControllerStartUpException: Failed to start platform router: FAILED to start up the platform router
  FAILED to start: Failed to start platform router: FAILED to start up the platform router
• xscontroller_0.log shows:
  com.sap.xs2rt.controller.ControllerExceptions$ControllerStartUpException: Failed to start platform router: FAILED to start up the platform router
      at com.sap.xs2rt.controller.impl.ControllerImpl.startUpPlatformRouter(ControllerImpl.java:1514)
      at com.sap.xs2rt.controller.impl.ControllerImpl.lambda$startUp$7(ControllerImpl.java:734)
      ... 6 more
  Caused by: com.sap.xs2rt.server.router.PlatformRouter$RouterException: FAILED to start up the platform router
      at com.sap.xs2rt.server.impl.router.PlatformRouterAbstract.start(PlatformRouterAbstract.java:215)
      at com.sap.xs2rt.controller.impl.ControllerImpl.startUpPlatformRouter(ControllerImpl.java:1512)
      ... 6 more
  Caused by: java.io.IOException: error 28 - No space left on device

xscontroller, no space left, paltform router, failed to start up. , KBA , BC-XS-RT , XS Advanced Runtime / XS Controller , Problem