这经常是我们所说的镜像同步就是这么来的，如果断点续传呢？rsync完全可以做到这一点。man手册再次告诉我们：
--partial
By default, rsync will delete any partially transferred file if the transfer is
interrupted. In some circumstances it is more desirable to keep partially transferred
files. Using the --partial option tells rsync to keep the partial file which should
make a subsequent transfer of the rest of the file much faster.
--partial-dir=DIR
A better way to keep partial files than the --partial option is to specify a DIR that
will be used to hold the partial data (instead of writing it out to the destination
file). On the next transfer, rsync will use a file found in this dir as data to
speed up the resumption of the transfer and then delete it after it has served its
purpose.
默认的情况下，当rsync传输中断后，新的rsync传输将删除所有的未完成的残余文件片段，然后开始新的传输。而使用--partial后，将会进行我们所说的断点续传。
值得注意的是-P这个参数是综合了--partial --progress两个参数，所以rsync的断点续传可以用下面的例子来说明：
# rsync -avzP /tmp/bigfile cnangel@10.1.6.160:/tmp/bigfile
另外，还有两个参数也经常用到：
t：修改次数
r：递归方式