标题:Linux高级流量控制tc使用
作者:网友
日期:2022-07-15 12:02:51
内容:
率是基本在10%的基本范围内，目前是8%。
64 bytes from 192.168.253.129: icmp_seq=421 ttl=64 time=0.486 ms
64 bytes from 192.168.253.129: icmp_seq=422 ttl=64 time=0.413 ms
64 bytes from 192.168.253.129: icmp_seq=423 ttl=64 time=0.616 ms
^C
--- 192.168.253.129 ping statistics ---
426 packets transmitted, 390 received, 8% packet loss, time 425724ms
rtt min/avg/max/mdev = 0.144/64.257/120.621/49.069 ms
如果数据包有重复的情况下，该如何处理。比如重复包的比例，我们设置为50%。
>tc qdisc add dev eth2 root netem duplicate 50%
使用ping的结果如下：
PING 192.168.253.128 (192.168.253.128) 56(84) bytes of data.
64 bytes from 192.168.253.128: icmp_seq=1 ttl=64 time=0.402 ms
64 bytes from 192.168.253.128: icmp_seq=1 ttl=64 time=0.409 ms (DUP!)
64 bytes from 192.168.253.128: icmp_seq=2 ttl=64 time=0.788 ms
64 bytes from 192.168.253.128: icmp_seq=3 ttl=64 time=0.887 ms
64 bytes from 192.168.253.128: icmp_seq=4 ttl=64 time=0.721 ms
64 bytes from 192.168.253.128: icmp_seq=4 ttl=64 time=0.757 ms (DUP!)
64 bytes from 192.168.253.128: icmp_seq=5 ttl=64 time=1.33 ms
比如产生坏包的情况。
tc qdisc add dev eth2 root netem corrupt 50%
ping的结果如下：
64 bytes from 192.168.253.128: icmp_seq=51 ttl=64 time=0.468 ms
64 bytes from 192.168.253.128: icmp_seq=52 ttl=64 time=0.822 ms
wrong data byte #23 should be 0x17 but was 0x15
#16 10 11 12 13 14 15 16 15 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
#48 30 31 32 33 34 35 36 37
64 bytes from 192.168.253.128: icmp_seq=53 ttl=64 time=1.71 ms
wrong data byte #53 should be 0x35 but was 0x37
#16 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
#48 30 31 32 33 34 37 36 37
64 bytes from 192.168.253.128: icmp_seq=54 ttl=64 time=0.000 ms
64 bytes from 192.168.253.128: icmp_seq=56 ttl=64 time=0.000 ms
如果包是乱序的，我们可以加入随机性，25%的包立即发送，其他的包延时10毫秒，系数为50%
[root@oel641 ~]# tc qdisc change dev eth2 root netem delay 10ms reorder 25% 50%
ping的结果如下所示：
64 bytes from 192.168.253.128: icmp_seq=200 ttl=64 time=1.24 ms
64 bytes from 192.168.253.128: icmp_seq=201 ttl=64 time=0.587 ms
64 bytes from 192.168.253.128: icmp_seq=202 ttl=64 time=1.01 ms
64 bytes from 192.168.253.128: icmp_seq=203 ttl=64 time=0.790 ms
64 bytes from 192.168.253.128: icmp_seq=204 ttl=64 time=0.998 ms
64 bytes from 192.168.253.128: icmp_seq=205 ttl=64 time=0.285 ms
64 bytes from 192.168.253.128: icmp_seq=206 ttl=64 time=0.882 ms
如果更复杂的场景呢，比如我们可以考虑加入流量的限制，网速控制在256k，最大延迟为50ms
[root@oel641 ~]# tc qdisc add dev eth2 root handle 1:0 netem delay 100ms
[root@oel641 ~]# tc qdisc add dev eth2 parent 1:1 handle 10: tbf rate 256kbit burst 10000 latency 50ms
速率 256kbit 突发传输 10k 最大延迟 50ms
如果不做流量控制，默认的情况下，传输可以达到90M美妙。
[root@oel642 ~]# scp 192.168.253.128:~/Percona-Server-5.6.14-rel62.0-483.Linux.x86_64.tar.gz .
Percona-Server-5.6.14-rel62.0-483.Linux.x86_64.tar.gz 100% 93MB 92.9MB/s 00:01
而如果设置了流量控制的场景，就绝对保持在一个指定范围内。
[root@oel642 ~]# scp 192.168.253.128:~/Percona-Server-5.6.14-rel62.0-483.Linux.x86_64.tar.gz .
Percona-Server-5.6.14-rel62.0-483.Linux.x86_64.tar.gz 0% 208KB 16.8KB/s 1:34:05 ETA
当然上面的场景都需要在测试环境先模拟一下，要不出现意料之外的问题就得不偿失了。
（编辑：错新网）