title: HDFS block size Vs actual file size
body: <p>I know that HDFS stores data using the regular linux file system in the data nodes. My HDFS block size is <code>128 MB</code>. Lets say that I have <code>10 GB</code> of disk space in my hadoop cluster that means, HDFS initially has <code>80 blocks</code> as available storage.</p>
  
  <p>If I create a small file of say <code>12.8 MB</code>, #available HDFS blocks will become 79. What happens if I create another small file of <code>12.8 MB</code>? Will the #availbale blocks stay at 79 or will it come down to 78? In the former case, HDFS basically recalculates the #available blocks after each block allocation based on the available free disk space so, #available blocks will become 78 only after more than 128 MB of disk space is consumed. Please clarify.</p>