When 1000 get status requests were sent at the concurrency of 462 from httperf wso2 esb gives following errors 2009-03-11 05:25:59,549 [127.0.1.1-damitha-laptop] [HttpCoreNIOListener] WARN HttpCoreNIOListener System may be unstable: IOReactor encountered a checked exception : Too many open files java.io.IOException: Too many open files at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method) at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:145) at org.apache.http.impl.nio.reactor.DefaultListeningIOReactor.processEvent(DefaultListeningIOReactor.java:115) at org.apache.http.impl.nio.reactor.DefaultListeningIOReactor.processEvents(DefaultListeningIOReactor.java:99) at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor.execute(AbstractMultiworkerIOReactor.java:160) at org.apache.synapse.transport.nhttp.HttpCoreNIOListener.startServerEngine(HttpCoreNIOListener.java:129) at org.apache.synapse.transport.nhttp.HttpCoreNIOListener.access$200(HttpCoreNIOListener.java:61) at org.apache.synapse.transport.nhttp.HttpCoreNIOListener$2.run(HttpCoreNIOListener.java:277) at java.lang.Thread.run(Thread.java:619) And also following warning 2009-03-11 05:31:37,261 [127.0.1.1-damitha-laptop] [HttpServerWorker-18] WARN HttpCoreNIOSender Connection closed by client : 127.0.0.1 I get the following registry error when testing with large concurrency and test loads sending subscriber insert requests [2009-03-13 10:17:05,839] ERROR - Could not write an error message as the headers & HTTP status were already committed! {org.apache.abdera.protocol.server.servlet.AbderaServlet} [2009-03-13 10:17:06,564] ERROR - Error servicing request {org.apache.abdera.protocol.server.servlet.AbderaServlet} org.apache.abdera.parser.stax.FOMException: com.ctc.wstx.exc.WstxIOException: null at org.apache.abdera.parser.stax.FOMElement.writeTo(FOMElement.java:405) at org.apache.abdera.parser.stax.FOMWriter.writeTo(FOMWriter.java:77) at org.apache.abdera.util.AbstractWriter.writeTo(AbstractWriter.java:82) at org.apache.abdera.parser.stax.FOMElement.writeTo(FOMElement.java:368) at org.apache.abdera.parser.stax.FOMElement.writeTo(FOMElement.java:391) at org.apache.abdera.protocol.server.context.BaseResponseContext.writeTo(BaseResponseContext.java:84) at org.apache.abdera.protocol.server.servlet.AbderaServlet.output(AbderaServlet.java:129) at org.apache.abdera.protocol.server.servlet.AbderaServlet.service(AbderaServlet.java:90) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.eclipse.equinox.http.helper.ContextPathServletAdaptor.service(ContextPathServletAdaptor.java:36) at org.eclipse.equinox.http.servlet.internal.ServletRegistration.handleRequest(ServletRegistration.java:90) at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:111) at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:67) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.wso2.carbon.bridge.BridgeServlet.service(BridgeServlet.java:116) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:870) at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665) at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528) at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:685) at java.lang.Thread.run(Thread.java:619) Caused by: com.ctc.wstx.exc.WstxIOException: null at com.ctc.wstx.sw.BaseStreamWriter.flush(BaseStreamWriter.java:313) at org.apache.axiom.om.impl.MTOMXMLStreamWriter.flush(MTOMXMLStreamWriter.java:146) at org.apache.axiom.om.impl.llom.OMNodeImpl.serialize(OMNodeImpl.java:462) at org.apache.abdera.parser.stax.FOMElement.writeTo(FOMElement.java:403) ... 29 more Caused by: ClientAbortException: java.net.SocketException: Broken pipe at org.apache.catalina.connector.OutputBuffer.doFlush(OutputBuffer.java:327) at org.apache.catalina.connector.OutputBuffer.flush(OutputBuffer.java:293) at org.apache.catalina.connector.CoyoteOutputStream.flush(CoyoteOutputStream.java:98) at sun.nio.cs.StreamEncoder.implFlush(StreamEncoder.java:278) at sun.nio.cs.StreamEncoder.flush(StreamEncoder.java:122) at java.io.OutputStreamWriter.flush(OutputStreamWriter.java:212) at com.ctc.wstx.sw.BufferingXmlWriter.flush(BufferingXmlWriter.java:214) at com.ctc.wstx.sw.BaseStreamWriter.flush(BaseStreamWriter.java:311) ... 32 more Caused by: java.net.SocketException: Broken pipe at java.net.SocketOutputStream.socketWrite0(Native Method) at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92) at java.net.SocketOutputStream.write(SocketOutputStream.java:136) at org.apache.coyote.http11.InternalOutputBuffer.realWriteBytes(InternalOutputBuffer.java:747) at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:432) at org.apache.coyote.http11.InternalOutputBuffer.flush(InternalOutputBuffer.java:305) at org.apache.coyote.http11.Http11Processor.action(Http11Processor.java:992) at org.apache.coyote.Response.action(Response.java:183) at org.apache.catalina.connector.OutputBuffer.doFlush(OutputBuffer.java:322) ... 39 more [2009-03-13 10:17:06,572] ERROR - Could not write an error message as the headers & HTTP status were already committed! {org.apache.abdera.protocol.server.servlet.AbderaServlet} When I send 10,000 get_status requests with concurrency at about 420 when it reaches about 8000 requests In registry console I get [2009-03-13 15:22:54,396] INFO - WSO2 Carbon started in 36 sec {org.wso2.carbon.core.StartupServlet} Mar 13, 2009 3:46:36 PM org.apache.tomcat.util.threads.ThreadPool logFull SEVERE: All threads (150) are currently busy, waiting. Increase maxThreads (150) or check the servlet status