Home > 工具介绍 > ss is one another utility to investigate sockets(特适合大规模tcp链接)

ss is one another utility to investigate sockets(特适合大规模tcp链接)

具体的可以参考这里

他的最大特点是快, 当你的系统有上万个tcp链接要了解的时候的时候, 你就知道我说什么了. netstat等常规工具变成废铁了, 这时候他的作用就非常明显了.

/proc interface is inadequate, unfortunately. When amount of sockets is enough large, netstat or even plain cat /proc/net/tcp/ cause nothing but pains and curses. In linux-2.4 the desease became worse: even if amount of sockets is small reading /proc/net/tcp/ is slow enough.

This utility presents a new approach, which is supposed to scale well. I am not going to describe technical details here and will concentrate on description of the command. The only important thing to say is that it is not so bad idea to load module tcp_diag, which can be found in directory Modules of iproute2. If you do not make this ss will work, but it falls back to /proc and becomes slow like netstat, well, a bit faster yet (see section “Some numbers”).

从技术上讲, 它主要是通过/proc来获取各种各样的统计信息. 特别是当处理tcp的时候用到了, tcp_diag功能. tcp_diag是tcp协议栈用于诊断和统计的一个模块, 用netfilter来获取第一手的信息的.  ss就用到了这个技术, 保证了信息的快捷获取.

这个软件是隶属于iproute包的,  如果你的系统没有的话可以这样安装:

apt-get  -y install iproute

用它可以了解下协议栈占用的内存, 每个链接的队列使用情况, 每个链接属于哪个进程.
而之前唯一能用的就是:

watch -n  1 'cat /proc/net/sockstat'

下面简单介绍下他的使用:

root@ubuntu:/usr/src/iproute-20090324/misc# ss --help
Usage: ss [ OPTIONS ]
ss [ OPTIONS ] [ FILTER ]
-h, --help           this message
-V, --version        output version information
-n, --numeric        don't resolve service names
-r, --resolve       resolve host names
-a, --all            display all sockets
-l, --listening      display listening sockets
-o, --options       show timer information
-e, --extended      show detailed socket information
-m, --memory        show socket memory usage
-p, --processes      show process using socket
-i, --info           show internal TCP information
-s, --summary        show socket usage summary

-4, --ipv4          display only IP version 4 sockets
-6, --ipv6          display only IP version 6 sockets
-0, --packet display PACKET sockets
-t, --tcp            display only TCP sockets
-u, --udp            display only UDP sockets
-d, --dccp           display only DCCP sockets
-w, --raw            display only RAW sockets
-x, --unix           display only Unix domain sockets
-f, --family=FAMILY display sockets of type FAMILY

-A, --query=QUERY
QUERY := {all|inet|tcp|udp|raw|unix|packet|netlink}[,QUERY]

-F, --filter=FILE   read filter information from FILE
FILTER := [ state TCP-STATE ] [ EXPRESSION ]
root@ubuntu:/usr/src/iproute-20090324/misc# ss -s
Total: 750 (kernel 761)
TCP:   21 (estab 7, closed 0, orphaned 0, synrecv 0, timewait 0/0), ports 0

Transport Total     IP        IPv6
*         761       -         -
RAW       0         0         0
UDP       3         3         0
TCP       21        18        3
INET      24        21        3
FRAG      0         0         0
root@ubuntu:/usr/src/iproute-20090324/misc# ss -t -m
State       Recv-Q Send-Q                                                                     Local Address:Port                                                                         Peer Address:Port
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:4251
mem:(r0,w0,f4096,t0)
CLOSE-WAIT  38     0                                                                        192.168.235.147:13910                                                                        174.36.30.67:https
mem:(r672,w0,f3424,t0)
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:4635
mem:(r0,w0,f4096,t0)
ESTAB       0      0                                                                              127.0.0.1:4369                                                                            127.0.0.1:54620
mem:(r0,w0,f0,t0)
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:1095
mem:(r0,w0,f4096,t0)
ESTAB       0      0                                                                              127.0.0.1:4369                                                                            127.0.0.1:44234
mem:(r0,w0,f0,t0)
ESTAB       0      0                                                                              127.0.0.1:54620                                                                           127.0.0.1:4369
mem:(r0,w0,f0,t0)
ESTAB       0      0                                                                              127.0.0.1:44234                                                                           127.0.0.1:4369
mem:(r0,w0,f0,t0)
root@ubuntu:/usr/src/iproute-20090324/misc# ss -p
State       Recv-Q Send-Q                                                                     Local Address:Port                                                                         Peer Address:Port
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:4251     users:(("sshd",8373,3))
CLOSE-WAIT  38     0                                                                        192.168.235.147:13910                                                                        174.36.30.67:https    users:(("dropbox",2674,13))
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:4635     users:(("sshd",350,3))
ESTAB       0      0                                                                              127.0.0.1:4369                                                                            127.0.0.1:54620    users:(("epmd",28338,5))
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:1095     users:(("sshd",29044,3))
ESTAB       0      0                                                                              127.0.0.1:4369                                                                            127.0.0.1:44234    users:(("epmd",28338,4))
ESTAB       0      0                                                                              127.0.0.1:54620                                                                           127.0.0.1:4369     users:(("beam.smp",25947,11))
ESTAB       0      0                                                                              127.0.0.1:44234                                                                           127.0.0.1:4369     users:(("inet_gethost",23783,8),("inet_gethost",23784,8))
root@ubuntu:/usr/src/iproute-20090324/misc# ss -i
State       Recv-Q Send-Q                                                                     Local Address:Port                                                                         Peer Address:Port
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:4251
cubic rto:396 rtt:124.5/66 ato:40 cwnd:4 send 375.3Kbps rcv_rtt:296456 rcv_space:66472
CLOSE-WAIT  38     0                                                                        192.168.235.147:13910                                                                        174.36.30.67:https
cubic wscale:7,9 rto:612 rtt:256/52 ato:40 cwnd:5 send 213.8Kbps rcv_rtt:259 rcv_space:5840
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:4635
cubic rto:356 rtt:144/33 ato:40 cwnd:4 send 324.4Kbps rcv_rtt:511258 rcv_space:46760
ESTAB       0      0                                                                              127.0.0.1:4369                                                                            127.0.0.1:54620
cubic wscale:9,9 rto:204 rtt:4/2 ato:40 cwnd:3 send 98.3Mbps rcv_space:32768
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:1095
cubic rto:232 rtt:21/18 ato:40 cwnd:5 ssthresh:4 send 2.8Mbps rcv_rtt:173516 rcv_space:118904
ESTAB       0      0                                                                              127.0.0.1:4369                                                                            127.0.0.1:44234
cubic wscale:9,9 rto:204 rtt:4/2 ato:40 cwnd:3 send 98.3Mbps rcv_space:32768
ESTAB       0      0                                                                              127.0.0.1:54620                                                                           127.0.0.1:4369
cubic wscale:9,9 rto:204 rtt:4/2 ato:40 cwnd:3 send 98.3Mbps rcv_space:32792
ESTAB       0      0                                                                              127.0.0.1:44234                                                                           127.0.0.1:4369
cubic wscale:9,9 rto:204 rtt:4/2 ato:40 cwnd:3 send 98.3Mbps rcv_space:32792
root@ubuntu:/usr/src/iproute-20090324/misc# ss -e
State       Recv-Q Send-Q                                                                     Local Address:Port                                                                         Peer Address:Port
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:4251     timer:(keepalive,50min,0) ino:1843366 sk:c2ea2600
CLOSE-WAIT  38     0                                                                        192.168.235.147:13910                                                                        174.36.30.67:https    ino:12200 sk:c2ea2140
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:4635     timer:(keepalive,2min59sec,0) ino:1101514 sk:c2ea4740
ESTAB       0      0                                                                              127.0.0.1:4369                                                                            127.0.0.1:54620    ino:2309430 sk:c2ea2ac0
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:1095     timer:(keepalive,6min59sec,0) ino:379842 sk:c2f4af80
ESTAB       0      0                                                                              127.0.0.1:4369                                                                            127.0.0.1:44234    ino:2044745 sk:c2ea3440
ESTAB       0      0                                                                              127.0.0.1:54620                                                                           127.0.0.1:4369     ino:2309429 sk:c2ea7200
ESTAB       0      0                                                                              127.0.0.1:44234                                                                           127.0.0.1:4369     ino:2044744 sk:c2ea1300
root@ubuntu:/usr/src/iproute-20090324/misc# ss -o
State       Recv-Q Send-Q                                                                     Local Address:Port                                                                         Peer Address:Port
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:4251     timer:(keepalive,50min,0)
CLOSE-WAIT  38     0                                                                        192.168.235.147:13910                                                                        174.36.30.67:https
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:4635     timer:(keepalive,2min50sec,0)
ESTAB       0      0                                                                              127.0.0.1:4369                                                                            127.0.0.1:54620
ESTAB       0      0                                                                        192.168.235.147:ssh                                                                       192.168.235.155:1095     timer:(keepalive,6min50sec,0)
ESTAB       0      0                                                                              127.0.0.1:4369                                                                            127.0.0.1:44234
ESTAB       0      0                                                                              127.0.0.1:54620                                                                           127.0.0.1:4369
ESTAB       0      0                                                                              127.0.0.1:44234                                                                           127.0.0.1:4369

Have fun!!!

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  1. icoolsea
    December 30th, 2014 at 11:46 | #1

    请教下霸爷,ss -s 出来的closed数目异常(一直积累到几十万不会释放,其他状态正常)可能和那些因素有关?(个别服务器存在此问题)谢谢。

    信息如下:
    Total: 717825 (kernel 717929)
    TCP: 718937 (estab 2098, closed 716067, orphaned 4, synrecv 0, timewait 148/0), ports 1432

    Transport Total IP IPv6
    * 717929 – –
    RAW 0 0 0
    UDP 22 19 3
    TCP 2870 2865 5
    INET 2892 2884 8
    FRAG 0 0 0

    [Reply]

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