NHLBI.ITAC has maintained a Dell/Isilon network attached storage (NAS) system for 7 years. This system is ever growing and the original arrays in the system have reached end of life (EOL). Purchasing Isilon Flex on Demand allows NHLBI/ITAC to continue to maintain the remaining arrays in the cluster as well as allowing Dell to manage the growing capacity and add new arrays as needed to maintain a safe capacity level across the entire system.