Hadoop fs lookup for block size?

Question

In Hadoop fs how to lookup the block size for a particular file?

I was primarily interested in a command line, something like:

hadoop fs ... hdfs://fs1.d         


        

Answer 1

The fsck commands in the other answers list the blocks and allow you to see the number of blocks. However, to see the actual block size in bytes with no extra cruft do:

hadoop fs -stat %o /filename

Default block size is:

hdfs getconf -confKey dfs.blocksize

Details about units

The units for the block size are not documented in the hadoop fs -stat command, however, looking at the source line and the docs for the method it calls we can see it uses bytes and cannot report block sizes over about 9 exabytes.

The units for the hdfs getconf command may not be bytes. It returns whatever string is being used for dfs.blocksize in the configuration file. (This is seen in the source for the final function and its indirect caller)