What can I do to speed up my file system copy

Just like the title,what can I do to speed up my file system copy.I heard about that using cache can speed up big file's copy,but I don't know how to do that.If possible,I prefer that when I copy some small files, the system don't use cache but write on the harddisk immediately,but when I copy a file that it is bigger than a specific size,the system use the cache to speed up the operate.I also heard that NFS server have some feature like this,but I am not sure,because I really know little about this.