问题现象：
使用Cosbench 0.4.2.c4 版本测试Ceph RGW read test失败，遇到异常如下：
FreeMarker template error: The following has evaluated to null or missing: ==> info.errorStatistics.stackTraceAndMessage[trace] [in template "mission.ftl" at line 238, column 48] Tip: If the failing expression is known to be legally null/missing, either specify a default value with myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing. (These only cover the last step of the expression; to cover the whole expression, use parenthessis: (myOptionVar.foo)!myDefault, (myOptionVar.foo)?? The failing instruction (FTL stack trace): ---------- ==> ${info.errorStatistics.stackTraceAndM... [in template "mission.ftl" at line 238, column 46] #list info.errorStatistics.stackTrace... [in template "mission.ftl" at line 232, column 9] #if showErrorStatistics [in template "mission.ftl" at line 223, column 5] ---------- Java stack trace (for programmers): ---------- freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...] at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:98) at freemarker.core.EvalUtil.coerceModelToString(EvalUtil.java:382) at freemarker.core.Expression.evalAndCoerceToString(Expression.java:115) at freemarker.core.DollarVariable.accept(DollarVariable.java:76) at freemarker.core.Environment.visit(Environment.java:265) at freemarker.core.MixedContent.accept(MixedContent.java:93) at freemarker.core.Environment.visit(Environment.java:265) at freemarker.core.IteratorBlock$Context.runLoop(IteratorBlock.java:181) at freemarker.core.Environment.visitIteratorBlock(Environment.java:509) at freemarker.core.IteratorBlock.accept(IteratorBlock.java:103) at freemarker.core.Environment.visit(Environment.java:265) at freemarker.core.MixedContent.accept(MixedContent.java:93) at freemarker.core.Environment.visit(Environment.java:265) at freemarker.core.IfBlock.accept(IfBlock.java:84) at freemarker.core.Environment.visitByHiddingParent(Environment.java:286) at freemarker.core.ConditionalBlock.accept(ConditionalBlock.java:86) at freemarker.core.Environment.visit(Environment.java:265) at freemarker.core.MixedContent.accept(MixedContent.java:93) at freemarker.core.Environment.visit(Environment.java:265) at freemarker.core.Environment.process(Environment.java:243) at freemarker.template.Template.process(Template.java:277) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.processTemplate(FreeMarkerView.java:366) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.doRender(FreeMarkerView.java:283) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.renderMergedTemplateModel(FreeMarkerView.java:233) at org.springframework.web.servlet.view.AbstractTemplateView.renderMergedOutputModel(AbstractTemplateView.java:167) at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250) at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1047) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:817) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549) at javax.servlet.http.HttpServlet.service(HttpServlet.java:690) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Thread.java:745)
原因： 软件bug 解决不彻底。 测试归档数据损坏导致此异常。 具体可以参考https://github.com/intel-cloud/cosbench/issues/288描述
解决方法：
将删除cosbench 安装目录中的archive目录内的已经生产的测试数据文件全部删除， 重启cosbench进程即可。