Read Short Circuit HDFS

Question

According to the documentation , reading short circuits is faster because they do not pass through node data. If so, then

• Why is this not enabled by default?
• In what scenarios do we need to read a short circuit?

Answer 1

Take a look at this article: http://blog.cloudera.com/blog/2013/08/how-improved-short-circuit-local-reads-bring-better-performance-and-security-to-hadoop/

Summary of the article:

, . . , hbers, kerberos.

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, . , . , Hadoop .