ccah-500 第42题 want to set and enforce a block size of 128MB for all new files written to the cluster

42.You're upgrading a Hadoop cluster from HDFS and MapReduce version 1 (MRv1) to one running HDFS and MapReduce version 2 (MRv2) on YARN. You want to set and enforce version
1 (MRv1) to one running HDFS and MapReduce version 2 (MRv2) on YARN. You want to set and enforce a block size of 128MB for all new files written to the cluster after upgrade. What should you do?

A. You cannot enforce this, since client code can always override this value

B. Set dfs.block.size to 128M on all the worker nodes, on all client machines, and on the NameNode, and set the parameter to final

C. Set dfs.block.size to 128 M on all the worker nodes and client machines, and set the parameter to final. You do not need to set this value on the NameNode

D. Set dfs.block.size to 134217728 on all the worker nodes, on all client machines, and on the NameNode, and set the parameter to final

E. Set dfs.block.size to 134217728 on all the worker nodes and client machines, and set the parameter to final. You do not need to set this value on the NameNode

Answer: C -- > E

 

Not C just because of the space between 128 and M;

有点诡异，怀疑题目描述问题，欢迎探讨。

 

refrence:
http://www.aiotestking.com/cloudera/what-should-you-do-4/
 

dfs.block.size
以字节计算的新建 HDFS
文件默认块大小。请注意该值也用作 HBase
区域服务器 HLog
块大小。

The default block size for new files, in bytes. You can use the following suffix (case insensitive): k(kilo), m(mega), g(giga), t(tera), p(peta), e(exa) to specify the size
(such as 128k, 512m, 1g, etc.), Or provide complete size in bytes (such as 134217728 for 128 MB).