虚拟内存和文件缓存，调大就行了 http://video.baidu.com/v?ct=301989888&rn=20&pn=0&db=0&s=19&rsp=1&word=%C9%E8%D6%C3%D0%E9%C4%E2%C4%DA%B4%E6&fbl=1024
