This is a question to test the basic concepts of HDFS. In HDFS, all the data is stored in blocks. The size of block can be configured in HDFS.
In Apache Hadoop, the default block size is 64 MB. To store a file of 25 MB size, at least one block will be allocated. This means at least 64 MB will be allocated for the file of 25 MB size.Read the full book at www.amazon.com