Getting the most out of flash storage


The speed limitations of disk drives compared to are well known. Less well known are the disk acrobatics administrators have to endure to configure drives for performance. This includes buying expensive disk drives and configuring them in complex schemes that use only a portion of the drive platter to boost performance, which means adding stacks of disks with largely unused capacity that administrators must monitor for failure (not to mention the costs for power, cooling and space to house the systems).


But even with these acrobatics, disks often struggle to meet required performance levels due to the distance of external disk storage systems from the CPU, as shown in Figure 1. While CPUs and memory operate in microseconds, access to external disk-based systems happens in milliseconds -- a thousandfold difference. Even when disk systems can pull data quickly, getting the data to and from the CPU has a long latency delay causing CPUs to spend a lot of time waiting for data. This negatively impacts application and database performance.

If you consider flash as a new form of media, like tape and disk drives are media, then implementing it the same way you implemented previous media technologies is only a small part of the way forward.