About hadoop performance testing issue

I set up a pseudo-distributed system consisting of three machines were hdp0 hdp1 hdp1 which hdp0 as the other two as namenode datanode. When formatting and build a normal startup , but why do I use TestDFSIO test run to the following so that cardholders do not move , seeking guidance thanks
hadoop @ hdp0: ~ / hadoop-0.20.203.0 $ bin / hadoop jar hadoop-test-0.20.203.0.jar TestDFSIO-read-nrFiles 10-fileSize 100
TestDFSIO.0.0.4
12/03/27 00:26:05 INFO fs.TestDFSIO: nrFiles = 10
12/03/27 00:26:05 INFO fs.TestDFSIO: fileSize (MB) = 100
12/03/27 00:26:05 INFO fs.TestDFSIO: bufferSize = 1000000
12/03/27 00:26:06 INFO fs.TestDFSIO: creating control file: 100 mega bytes, 10 files
12/03/27 00:26:07 INFO fs.TestDFSIO: created control files for: 10 files
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landlord of the problem solved it ? I also met the same problem do not know why uh
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uh. . Well, I suddenly resolved. . . Just because it is relatively slow , the landlord has been placed not to move , much can wait out
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but I do not really understand it I use the sentence is $ bin / hadoop jar ; hadoop-test-0.20.203.0.jar TestDFSIO-write-nrFiles 10-fileSize 1000