A cache management method, where a first process obtains a first I/O request corresponding to the first process. When a current first memory space (which is a section of space in a shared memory pool of the computing cluster, and shared by the first process and the second process) of the first process is insufficient to store data corresponding to the first I/O request, the first process sends a first cache application instruction to the cache service process, to apply for allocation of a second memory space in the shared memory pool. A second process obtains a second I/O request corresponding to the second process. When the first memory space corresponding to the second process is insufficient to store data corresponding to the second I/O request, the second process sends a second cache application instruction to the cache service process, to apply for allocation of the second memory space.