The definition, characteristics, and classification of big data along with some
discussions on cloud computing are introduced. The relationship between big data and
cloud computing, big data storage systems, and Hadoop technology are also discussed.
Furthermore, research challenges are investigated, with focus on scalability, availability,
data integrity, data transformation, data quality, data heterogeneity, privacy, legal and
regulatory issues, and governance. Lastly, open research issues that require substantial
research efforts are summarized.