In this paper, we present a low-overhead strategy and its
implementation for using flash memory as an extended cache
for a recoverable database.
This method is referred to as Flash
as Cache Extension or FaCE for short. Like any other caching
mechanism, the objective of FaCE is to provide the performance
of flash memory and the capacity of disk at as little
cost as possible.
We set out to achieve this with the realization
that flashmemory has drastically different characteristics
(such as no overwriting, slow writes, and nonvolatility) than
DRAM buffer, and they must be dealt with carefully and
exploited effectively.
There are a few existing approaches
that store frequently accessed data in flash memory drives by
using them as either faster disk drives or an extension to the
RAM buffer.
The FaCE method we propose is in line with
the existing approaches using flash memory as an extension
to the DRAM buffer, but it is also different from them in
several ways.