Oracle Database Smart Flash Cache is a feature that was first introduced with Oracle Database 11g Release 2. Only available on Oracle Linux and Oracle Solaris, this feature increases the size of the database buffer cache without having to add RAM to the system. In effect, it acts as a second level cache on flash memory and will especially benefit read-intensive database applications.

The Oracle Database Smart Flash Cache white paper concludes:

Available at no additional cost, Database Smart Flash Cache on Oracle Solaris and Oracle Linux has the potential to offer considerable benefit to users of Oracle Database 11g Release 2 with disk-bound read-mostly or read-only workloads, through the simple addition of flash storage such as the Sun Storage F5100 Flash Array or the Sun Flash Accelerator F20 PCIe Card.