Capacity Plus for VSAM has a number of features which allow you to achieve maximum compression with the highest degree of integrity, improve response time, and speed system throughput.
It efficiently reduces the amount of data passing through I/O channels by a degree corresponding to the level of compression. Since compression allows more data to fit in each control interval (CI), Capacity Plus for VSAM reduces the number of CIs and results in fewer index records and fewer reads needed to access data.