VSAM Performance Enhancement › Advanced Topics › Optimizing VSAM Performance by Adjusting VSAM Parameters › CISZ (Data Component CI Size)

CISZ (Data Component CI Size)

VPE flags all data component CI sizes of less than 2048 bytes. These small CI sizes result in reduced space utilization. Larger data component CI sizes result in improved space utilization. In addition, small data component CI sizes increase the number of physical reads required to process a file sequentially. These small sizes are generally a holdover from 3330 disk devices and channels with speeds of 1.5 Mb-per-second.