The EMC Cache Layer
A storage-system cache has two parts: a read cache and a write cache. The read cache uses a read-ahead mechanism that lets the storage system prefetch data from the disk. Therefore the data will be ready in the cache when the application needs it. The write cache buffers and optimizes writes by absorbing peak loads, combining small writes, and eliminating rewrites.
Measure the extent and effectiveness of cache usage using the test mapped to this layer.
Figure 1 : The EMS Cache Layer