HDFS 上的文件块
Hadoop是否保证同一文件的不同块将存储在集群中的不同机器上？显然，复制的块将位于不同的机器上。
Does Hadoop guarantee that different blocks from same file will be stored on different machines in the cluster? Obviously replicated blocks will be on different machines.
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不会。如果您查看HDFS 架构指南，您将看到（在图中）文件
part-1的复制因子为 3，并且由标记为 2、4 和 5 的三个块组成。请注意块 2 和 5 的结构在一种情况下，在同一个数据节点上。No. If you look at the HDFS Architecture Guide, you'll see (in the diagram) that file
part-1has a replication factor of 3, and is made up of three blocks labelled 2, 4, and 5. Note how blocks 2 and 5 are on the same Datanode in one case.显然不是： http://hadoop.apache.org/common/ docs/r0.20.2/hdfs_user_guide.html#Rebalancer
Apparently not: http://hadoop.apache.org/common/docs/r0.20.2/hdfs_user_guide.html#Rebalancer
我认为恰恰相反。撇开复制不谈，每个数据节点将每个数据块存储为本地文件系统中自己的文件。
On the contrary I think. Setting aside replication, each datanode stores each block of data as its own file in the local file system.
Hadoop 并不能保证这一点。由于这会带来巨大的安全损失，因此如果您在作业中请求文件，则宕机的数据节点将导致整个作业失败。只是因为块不可用。无法想象您的问题的用例，也许您可以多说一些以了解您的真正意图。
Well Hadoop does not guarantee that. Since that is a huge loss of security, if you are requesting a file within a job, a downed datanode will cause the complete job to fail. Just because a block is not available. Can't imagine a usecase for your question, maybe you can tell a bit more to understand what your intention really was.