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)

解决方案：

1. stop all cosbench processes (controller, drivers)
2. edit cosbench-start.sh, locate the java launching line, and add "-Dcom.amazonaws.services.s3.disableGetObjectMD5Validation=true"
3. restart cosbench processes.