You want to do mostly full table scans on your data. In order to improve performance you increase

your block size. Why does this improve your scan performance?

A.
It does not. Increasing block size does not improve scan performance.

B.
It does not. Increasing block size means that fewer blocks fit into your block cache. This
requires HBase to read each block from disk rather than cache for each scan, thereby decreasing
scan performance.

C.
Increasing block size requires HBase to read from disk fewer times, thereby increasing scan
performance.

D.
Increasing block size means fewer block indexes that need to be read from disk, thereby
increasing scan performance.

Explanation:
Change HFile block size to something bigger to improve scan (at cost of random
read).
Reference:Testing HBase Scan performance