并发加速 Rsync

https://stackoverflow.com/questions/24058544/speed-up-rsync-with-simultaneous-concurrent-file-transfers

rsync -avzh --rsh=ssh [email protected]:/home/bigzhu/project/back_end/follow_center_go/medias/ ./
ssh [email protected] ls -1 /home/bigzhu/project/back_end/follow_center_go/medias | xargs -I {} -P 5 -n 1 rsync -avzh [email protected]:/home/bigzhu/project/back_end/follow_center_go/medias/{} ./

简单来说, 就是把服务器目录列出来, 使用 xargs 分别对每个目录进行 rsync 操作, 限定并发 5