linux查看使用中的网卡是否打满

1、查看Linux系统有几块网卡
一般系统默认都有4个,无所谓了管它几个呢~

[root@db25440 ~]# ifconfig -a
eth0      Link encap:Ethernet  HWaddr D4:BE:D9:AA:30:18  
          inet addr:10.255.254.40  Bcast:10.255.255.255  Mask:255.255.240.0
          inet6 addr: fe80::d6be:d9ff:feaa:3018/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:4861130549 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5490188631 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1745950525499 (1.5 TiB)  TX bytes:2873870867512 (2.6 TiB)

eth1      Link encap:Ethernet  HWaddr D4:BE:D9:AA:30:1A  
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

eth2      Link encap:Ethernet  HWaddr D4:BE:D9:AA:30:1C  
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

eth3      Link encap:Ethernet  HWaddr D4:BE:D9:AA:30:1E  
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:9040433 errors:0 dropped:0 overruns:0 frame:0
          TX packets:9040433 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:15560955892 (14.4 GiB)  TX bytes:15560955892 (14.4 GiB)

[root@db25440 ~]# 

另外可以使用下面两种方式确定
cat /proc/net/dev
lspci | grep -i eth

2、确定网卡的带宽
ethtool命令用于获取以太网卡的配置信息，或者修改这些配置(这个命令比较复杂，功能特别多回头写一个命令解释)

[root@db25440 ~]# ethtool eth0
Settings for eth0:
    Supported ports: [ TP ]
    Supported link modes:   10baseT/Half 10baseT/Full 
                            100baseT/Half 100baseT/Full 
                            1000baseT/Full 
    Supported pause frame use: No
    Supports auto-negotiation: Yes
    Advertised link modes:  10baseT/Half 10baseT/Full 
                            100baseT/Half 100baseT/Full 
                            1000baseT/Full 
    Advertised pause frame use: No
    Advertised auto-negotiation: Yes  //自动协商开启 对应关闭配置为：No
    Speed: 1000Mb/s     //速度 1000Mb
    Duplex: Full        //全双工 对应配置还有Half
    Port: Twisted Pair
    PHYAD: 1
    Transceiver: internal
    Auto-negotiation: on
    MDI-X: Unknown
    Supports Wake-on: g
    Wake-on: d
    Link detected: yes  //eth0已经**
[root@db25440 ~]# 

先不用关注每一项的具体含义，先看Advertised link modes、Auto-negotiation、Duplex。首先连接模式、自动协商是否开启(在这里是开启的)、全双工
3、确定目前连接状态和速率

[root@db25440 ~]# mii-tool eth0
eth0: negotiated 100baseTx-FD, link ok
[root@db25440 ~]# 

4、根据使用的模式计算支持的最大带宽
网卡传输的计算单位是bit，所以当统计为Byte为单位时就需要转换 1byte=8bit
100Mbits=12.5MB
5、使用工具查看目前网卡上传和下载的使用量比如这里用dstat

root@db25440 ~]# dstat 
----total-cpu-usage---- -dsk/total- -net/total- ---paging-- ---system--
usr sys idl wai hiq siq| read  writ| recv  send|  in   out | int   csw 
  2   0  98   0   0   0|6740B 1257k|   0     0 |   0    60B|1012  2297 
  0   0 100   0   0   0|   0     0 |  17k   17k|   0     0 | 373   170 
  0   0 100   0   0   0|   0     0 |  25k   25k|   0     0 | 400   196 
  0   0 100   0   0   0|   0     0 |  20k   20k|   0     0 | 363   176 ^C
[root@db25440 ~]# 

对比就知道网卡是否打满

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