Determining how many mappers will run

Question

My Hadoop cluster’s HDFS block size is 64MB. I have a directory containing 100 plain text files, each of which is 100MB in size. The InputFormat for my job is TextInputFormat. Is there any way to determine how many Mappers will run in this case?

Can someone please help?

Thanks in advanace!

Answer 1

Here what happens is, each file would be split into two as the block size (64 MB) is less than the file size (100 MB), so 200 mappers would be running.