阿里云服务器|centos查看并发数&调优

男娘i 2023-06-19 09:51 15阅读 0赞

## 背景 ##

博主这几天发现服务器负载蹭蹭上涨，特此记录一篇：

> 借鉴这篇文章：[主要原因][Link 1]  
> 阿里云服务器配置：2H4G centos7  
> docker基础配置包含：taos\_img、mysql、[nginx][]、[nacos][]、[sentinel][]、[tinyid][]、**[jrebel-ls][]**、[showdoc][]、[nexus3][]、[jenkins][]服务

问题点（已解决）：

*  服务器异常卡顿
 *  命令严重延迟
 *  TCP连接丢失严重
 *  凉凉头开始大

查阅资料后发现以下问题：

命令：netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S[a]}'
    [root@iZuf6d9y2x6c8r92unymr1Z bak]# netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S[a]}'
    SYN_RECV 4
    CLOSE_WAIT 1
    ESTABLISHED 373
    FIN_WAIT1 1
    FIN_WAIT2 426
    TIME_WAIT 1013

![服务器效果图][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n_size_16_color_FFFFFF_t_70]

各个数据及其含义如下：
    CLOSED：无连接是活动的或正在进行
    LISTEN：服务器在等待进入呼叫
    SYN_RECV：一个连接请求已经到达，等待确认
    SYN_SENT：应用已经开始，打开一个连接
    ESTABLISHED：正常数据传输状态
    FIN_WAIT1：应用说它已经完成
    FIN_WAIT2：另一边已同意释放
    ITMED_WAIT：等待所有分组死掉
    CLOSING：两边同时尝试关闭
    TIME_WAIT：另一边已初始化一个释放
    LAST_ACK：等待所有分组死掉

**意思就是我的服务器有消除未被及时释放的TIME\_WAIT状态的TCP连接**  
在执行

[root@iZuf6d9y2x6c8r92unymr1Z bak]# netstat -pnt | grep :9001 | wc -l
    981

解决方案：

*  如发现系统存在大量TIME\_WAIT状态的连接，通过调整内核参数解决

[root@iZuf6d9y2x6c8r92unymr1Z bak]# vim /etc/sysctl.conf
    vm.swappiness = 0
    net.ipv4.neigh.default.gc_stale_time = 120
    
    # see details in https://help.aliyun.com/knowledge_detail/39428.html
    net.ipv4.conf.all.rp_filter = 0
    net.ipv4.conf.default.rp_filter = 0
    net.ipv4.conf.default.arp_announce = 2
    net.ipv4.conf.lo.arp_announce = 2
    net.ipv4.conf.all.arp_announce = 2
    
    # see details in https://help.aliyun.com/knowledge_detail/41334.html
    net.ipv4.tcp_max_tw_buckets = 5000
    net.ipv4.tcp_syncookies = 1
    net.ipv4.tcp_max_syn_backlog = 1024
    net.ipv4.tcp_synack_retries = 2
    
    net.ipv6.conf.all.disable_ipv6 = 1
    net.ipv6.conf.default.disable_ipv6 = 1
    net.ipv6.conf.lo.disable_ipv6 = 1
    kernel.sysrq = 1

*  在文件末尾追加了配置：

net.ipv4.tcp_syncookies = 1
    net.ipv4.tcp_tw_reuse = 1
    net.ipv4.tcp_tw_recycle = 1
    net.ipv4.tcp_fin_timeout = 30

> **然后执行 /sbin/sysctl -p 让参数生效**

[root@iZuf6d9y2x6c8r92unymr1Z bak]# /sbin/sysctl -p
    vm.swappiness = 0
    net.ipv4.neigh.default.gc_stale_time = 120
    net.ipv4.conf.all.rp_filter = 0
    net.ipv4.conf.default.rp_filter = 0
    net.ipv4.conf.default.arp_announce = 2
    net.ipv4.conf.lo.arp_announce = 2
    net.ipv4.conf.all.arp_announce = 2
    net.ipv4.tcp_max_tw_buckets = 5000
    net.ipv4.tcp_syncookies = 1
    net.ipv4.tcp_max_syn_backlog = 1024
    net.ipv4.tcp_synack_retries = 2
    net.ipv6.conf.all.disable_ipv6 = 1
    net.ipv6.conf.default.disable_ipv6 = 1
    net.ipv6.conf.lo.disable_ipv6 = 1
    kernel.sysrq = 1
    net.ipv4.tcp_tw_reuse = 1
    net.ipv4.tcp_tw_recycle = 1
    net.ipv4.tcp_fin_timeout = 30

过一段时间在查看：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n_size_16_color_FFFFFF_t_70 3]

[Link 1]: https://blog.csdn.net/qierkang/article/details/95095954
[nginx]: https://qekang.com
[nacos]: https://nacos.qekang.com/nacos
[sentinel]: https://sentinel.qekang.com/
[tinyid]: https://id.qekang.com/tinyid/id/nextId?bizType=test_odd&batchSize=50&token=fceed18c1867ddc65295be64bcff4160
[jrebel-ls]: https://jrebel.qekang.com
[showdoc]: https://showdoc.qekang.com
[nexus3]: https://nexus.qekang.com
[jenkins]: https://jenkins.qekang.com
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20191205181929233.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20191205182130833.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20191205182142653.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20191205182146740.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpZXJrYW5n,size_16,color_FFFFFF,t_70