In one embodiment, the present invention includes a method for writing
data to a disk if inserting the data into a cache, such as a disk cache
associated with the disk, would cause a threshold of dirty data in the
cache to be met or exceeded. Further, in certain embodiments, the cache
may store data according to a first cache policy and a second cache
policy. A determination of whether to store data according to the first
or second policies may be dependent upon an amount of dirty data in the
cache, in certain embodiments. In certain embodiments, the cache may
include at least one portion reserved for clean data.