spring-cloud-netflix: spring cloud zuul : could not acquire a semaphore for execution and no fallback available.

I used Spring cloud zuul as a gateway, but always reported a error , the loadrunner concurrency is 200 , and i set zuul.eureka.MSG-SERVICE.semaphore.maxSemaphores: 2000 , but still reported errors . com.netflix.zuul.exception.ZuulException: Forwarding error at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.handleException(RibbonRoutingFilter.java:158) ~[spring-cloud-netflix-core-1.1.4.RELEASE.jar!/:1.1.4.RELEASE] at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.forward(RibbonRoutingFilter.java:133) ~[spring-cloud-netflix-core-1.1.4.RELEASE.jar!/:1.1.4.RELEASE] at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.run(RibbonRoutingFilter.java:79) ~[spring-cloud-netflix-core-1.1.4.RELEASE.jar!/:1.1.4.RELEASE] at com.netflix.zuul.ZuulFilter.runFilter(ZuulFilter.java:112) ~[zuul-core-1.1.0.jar!/:1.1.0] at com.netflix.zuul.FilterProcessor.processZuulFilter(FilterProcessor.java:197) ~[zuul-core-1.1.0.jar!/:1.1.0] at com.netflix.zuul.FilterProcessor.runFilters(FilterProcessor.java:161) ~[zuul-core-1.1.0.jar!/:1.1.0] at com.netflix.zuul.FilterProcessor.route(FilterProcessor.java:120) ~[zuul-core-1.1.0.jar!/:1.1.0] at com.netflix.zuul.ZuulRunner.route(ZuulRunner.java:96) ~[zuul-core-1.1.0.jar!/:1.1.0] at com.netflix.zuul.http.ZuulServlet.route(ZuulServlet.java:116) ~[zuul-core-1.1.0.jar!/:1.1.0] at com.netflix.zuul.http.ZuulServlet.service(ZuulServlet.java:81) ~[zuul-core-1.1.0.jar!/:1.1.0] at org.springframework.web.servlet.mvc.ServletWrappingController.handleRequestInternal(ServletWrappingController.java:158) [spring-webmvc-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at org.springframework.cloud.netflix.zuul.web.ZuulController.handleRequestInternal(ZuulController.java:43) [spring-cloud-netflix-core-1.1.4.RELEASE.jar!/:1.1.4.RELEASE] at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:147) [spring-webmvc-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:50) [spring-webmvc-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:961) [spring-webmvc-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:895) [spring-webmvc-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:967) [spring-webmvc-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:869) [spring-webmvc-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) [javax.servlet-api-3.1.0.jar!/:3.1.0] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843) [spring-webmvc-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) [javax.servlet-api-3.1.0.jar!/:3.1.0] at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at org.springframework.boot.actuate.autoconfigure.EndpointWebMvcAutoConfiguration$ApplicationContextHeaderFilter.doFilterInternal(EndpointWebMvcAutoConfiguration.java:281) [spring-boot-actuator-1.3.6.RELEASE.jar!/:1.3.6.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at org.springframework.cloud.sleuth.instrument.web.TraceFilter.doFilter(TraceFilter.java:156) [spring-cloud-sleuth-core-1.0.3.RELEASE.jar!/:1.0.3.RELEASE] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at org.springframework.boot.actuate.trace.WebRequestTraceFilter.doFilterInternal(WebRequestTraceFilter.java:115) [spring-boot-actuator-1.3.6.RELEASE.jar!/:1.3.6.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:87) [spring-web-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77) [spring-web-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121) [spring-web-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at org.springframework.boot.actuate.autoconfigure.MetricsFilter.doFilterInternal(MetricsFilter.java:103) [spring-boot-actuator-1.3.6.RELEASE.jar!/:1.3.6.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.2.7.RELEASE.jar!/:4.2.7.RELEASE] at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46) [undertow-core-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60) [undertow-core-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43) [undertow-core-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:285) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:264) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:175) [undertow-servlet-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202) [undertow-core-1.3.23.Final.jar!/:1.3.23.Final] at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:802) [undertow-core-1.3.23.Final.jar!/:1.3.23.Final] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_95] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_95] at java.lang.Thread.run(Thread.java:745) [na:1.7.0_95] Caused by: com.netflix.hystrix.exception.HystrixRuntimeException: MSG-SERVICE could not acquire a semaphore for execution and no fallback available. at com.netflix.hystrix.AbstractCommand$21.call(AbstractCommand.java:783) ~[hystrix-core-1.5.3.jar!/:1.5.3] at com.netflix.hystrix.AbstractCommand$21.call(AbstractCommand.java:768) ~[hystrix-core-1.5.3.jar!/:1.5.3] at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.onError(OperatorOnErrorResumeNextViaFunction.java:139) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OperatorDoOnEach$1.onError(OperatorDoOnEach.java:71) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OperatorDoOnEach$1.onError(OperatorDoOnEach.java:71) ~[rxjava-1.1.5.jar!/:1.1.5] at com.netflix.hystrix.AbstractCommand$DeprecatedOnFallbackHookApplication$1.onError(AbstractCommand.java:1448) ~[hystrix-core-1.5.3.jar!/:1.5.3] at com.netflix.hystrix.AbstractCommand$FallbackHookApplication$1.onError(AbstractCommand.java:1373) ~[hystrix-core-1.5.3.jar!/:1.5.3] at rx.internal.operators.OperatorDoOnEach$1.onError(OperatorDoOnEach.java:71) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.observers.Subscribers$5.onError(Subscribers.java:224) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeThrow.call(OnSubscribeThrow.java:44) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeThrow.call(OnSubscribeThrow.java:28) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.Observable.unsafeSubscribe(Observable.java:8460) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.Observable.unsafeSubscribe(Observable.java:8460) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:50) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.Observable.subscribe(Observable.java:8553) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.Observable.subscribe(Observable.java:8520) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.internal.operators.BlockingOperatorToFuture.toFuture(BlockingOperatorToFuture.java:57) ~[rxjava-1.1.5.jar!/:1.1.5] at rx.observables.BlockingObservable.toFuture(BlockingObservable.java:401) ~[rxjava-1.1.5.jar!/:1.1.5] at com.netflix.hystrix.HystrixCommand.queue(HystrixCommand.java:373) ~[hystrix-core-1.5.3.jar!/:1.5.3] at com.netflix.hystrix.HystrixCommand.execute(HystrixCommand.java:329) ~[hystrix-core-1.5.3.jar!/:1.5.3] at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.forward(RibbonRoutingFilter.java:127) ~[spring-cloud-netflix-core-1.1.4.RELEASE.jar!/:1.1.4.RELEASE] ... 74 common frames omitted Caused by: java.lang.RuntimeException: could not acquire a semaphore for execution at com.netflix.hystrix.AbstractCommand.handleSemaphoreRejectionViaFallback(AbstractCommand.java:927) ~[hystrix-core-1.5.3.jar!/:1.5.3] at com.netflix.hystrix.AbstractCommand.applyHystrixSemantics(AbstractCommand.java:529) ~[hystrix-core-1.5.3.jar!/:1.5.3] at com.netflix.hystrix.AbstractCommand.access$100(AbstractCommand.java:59) ~[hystrix-core-1.5.3.jar!/:1.5.3] at com.netflix.hystrix.AbstractCommand$4.call(AbstractCommand.java:426) ~[hystrix-core-1.5.3.jar!/:1.5.3] at com.netflix.hystrix.AbstractCommand$4.call(AbstractCommand.java:423) ~[hystrix-core-1.5.3.jar!/:1.5.3] at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:46) ~[rxjava-1.1.5.jar!/:1.1.5] ... 92 common frames omitted

Thank you in Advance