限制網路頻寬

1. 如果不希望 rsync 遠端備份資料時佔用太大的網路頻寬而影響正常的服務，可以加上 -bwlimit 選項來指定資料傳輸的速度上限，單位是 KBPS，以下是沒有限制頻寬的速度，每秒 4.34M。

   [root@kvm5 ~]# rsync -avh /etc deyu1@kvm7.deyu.wang: | tail
   deyu1@kvm7.deyu.wang's password: 
   etc/yum/pluginconf.d/langpacks.conf
   etc/yum/pluginconf.d/priorities.conf
   etc/yum/protected.d/
   etc/yum/protected.d/systemd.conf
   etc/yum/vars/
   etc/yum/vars/contentdir
   etc/yum/vars/infra
   
   sent 19.51M bytes  received 19.08K bytes  4.34M bytes/sec
   total size is 19.44M  speedup is 1.00
   

2. 刪除 kvm7.deyu.wang 上的同步資料。

   [root@kvm7 ~]# rm -rf /home/deyu1/etc
   

3. 再以 bwlimit=100 參數，限制每秒 100K 的速度同步。

   [root@kvm5 ~]# rsync -avh --bwlimit=100 /etc deyu1@kvm7.deyu.wang: | tail
   deyu1@kvm7.deyu.wang's password: 
   etc/yum/pluginconf.d/langpacks.conf
   etc/yum/pluginconf.d/priorities.conf
   etc/yum/protected.d/
   etc/yum/protected.d/systemd.conf
   etc/yum/vars/
   etc/yum/vars/contentdir
   etc/yum/vars/infra
   
   sent 19.51M bytes  received 19.08K bytes  100.39K bytes/sec
   total size is 19.44M  speedup is 1.00