cosbench read异常解决办法。 Unable to verify integrity of data download. Client calculated content hash didn't match hash calculated by Amazon S3. The data may be corrupt.

问题：cosbench read测试failed 报错如下

Cosbench v0.4.2.c4 against Ceph (Hammer) / radosgw / HAproxy's HTTP end point. All seems fine except that at the end of the read test, it failed the task and gave following errors

com.amazonaws.AmazonClientException: Unable to verify integrity of data download.  Client calculated content hash didn't match hash calculated by Amazon S3.  The data may be corrupt.
        at com.amazonaws.services.s3.internal.DigestValidationInputStream.validateMD5Digest(DigestValidationInputStream.java:79)
        at com.amazonaws.services.s3.internal.DigestValidationInputStream.read(DigestValidationInputStream.java:61)
        at com.amazonaws.internal.SdkFilterInputStream.read(SdkFilterInputStream.java:72)
        at com.amazonaws.services.s3.model.S3ObjectInputStream.read(S3ObjectInputStream.java:155)
        at com.amazonaws.services.s3.model.S3ObjectInputStream.read(S3ObjectInputStream.java:147)
        at com.intel.cosbench.driver.operator.Reader.copyLarge(Reader.java:120)
        at com.intel.cosbench.driver.operator.Reader.doRead(Reader.java:92)
        at com.intel.cosbench.driver.operator.Reader.operate(Reader.java:69)
        at com.intel.cosbench.driver.operator.AbstractOperator.operate(AbstractOperator.java:76)
        at com.intel.cosbench.driver.agent.WorkAgent.performOperation(WorkAgent.java:197)
        at com.intel.cosbench.driver.agent.WorkAgent.doWork(WorkAgent.java:177)
        at com.intel.cosbench.driver.agent.WorkAgent.execute(WorkAgent.java:134)
        at com.intel.cosbench.driver.agent.AbstractAgent.call(AbstractAgent.java:44)
        at com.intel.cosbench.driver.agent.AbstractAgent.call(AbstractAgent.java:1)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)

　　

https://github.com/awslabs/aws-sdk-android-samples/issues/62

解决方案：

1. stop-all.sh 停止 cosbench 进程(controller, drivers)
2. 编辑 cosbench-start.sh 文件,找到java启动命令行参数, 增加"-Dcom.amazonaws.services.s3.disableGetObjectMD5Validation=true" 关闭S3的MD5校验功能
3. start-all.sh 启动所有的cosbench processes.