If you split the RACF® database between multiple data sets, you can reduce the effect of I/O on performance, because:

• Each data set might receive fewer requests
• Each data set might be smaller, in which case each request requires fewer I/O requests and fewer movements of the activator arm on the device
• Each data set can have up to 255 resident-data blocks, optimizing I/O and increasing the amount of in-storage data. See also Resident data blocks.