Development of technologies for the processing of \"Big data\" has recently been advanced by network-related enterprises. Apache Hadoop is attracting attention as an OSS that implements storage and distributed processing of petabyte-class big data by means of scaling out based on the above technologies. It has conducted the test for the ability of Apache Hadoop for enterprise use and has built systems according to its characteristics. For the sizing of Apache Hadoop that is usually regarded to be difficult, it has developed a technology for size prediction by means of simulation. This paper introduces these technologies.