proxy日志：

 96183:20210916:233624.125 cannot send list of active checks to "10.205.117.160": host [10.205.117.160] not found
 96474:20210916:233637.027 Zabbix agent item "ci[memory_model]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96611:20210916:233638.004 Zabbix agent item "ci[memory_number]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96441:20210916:233639.205 Zabbix agent item "ci[memory_size]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96560:20210916:233640.117 Zabbix agent item "ci[mount_device]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96530:20210916:233641.581 Zabbix agent item "ci[mount_fstype]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96445:20210916:233642.783 Zabbix agent item "ci[mount_options]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96620:20210916:233643.004 Zabbix agent item "ci[mount_point]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96443:20210916:233644.428 Zabbix agent item "ci[mount_size_available]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96545:20210916:233645.003 Zabbix agent item "ci[mount_size_total]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96478:20210916:233646.015 Zabbix agent item "ci[os_release]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96509:20210916:233647.189 Zabbix agent item "ci[os_version]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96580:20210916:233648.323 Zabbix agent item "ci[other_ip]" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96621:20210916:233649.459 Zabbix agent item "runuser_status" on host "10.205.122.6" failed: another network error, wait for 15 seconds
 96438:20210916:233734.004 Zabbix agent item "ci[app_ip]" on host "10.205.122.9" failed: first network error, wait for 15 seconds
 96666:20210916:233734.172 temporarily disabling Zabbix agent checks on host "10.205.122.6": host unavailable
 96471:20210916:233749.006 Zabbix agent item "ci[memory_model]" on host "10.205.122.9" failed: another network error, wait for 15 seconds
 96483:20210916:233750.014 Zabbix agent item "ci[memory_number]" on host "10.205.122.9" failed: another network error, wait for 15 seconds
 96459:20210916:233751.003 [Z3005] query failed: [1040] Too many connections [begin;]
 96459:20210916:233751.003 [Z3005] query failed: [1040] Too many connections [rollback;]
 96459:20210916:233751.003 cannot perform transaction rollback, connection will be reset
 96459:20210916:233751.004 [Z3001] connection to database 'zabbix_proxy' failed: [1040] Too many connections
 96459:20210916:233751.004 Cannot connect to the database. Exiting...
 96121:20210916:233751.048 One child process died (PID:96459,exitcode/signal:1). Exiting ...
 96121:20210916:233751.191 syncing history data...
 96121:20210916:233751.193 syncing history data... 100.000000%
 96121:20210916:233751.193 syncing history data done
 96121:20210916:233751.193 Zabbix Proxy stopped. Zabbix 5.0.10 (revision 7c3f43904c).
 

mysql 查询：

查询最大连接数

show variables like 'max_connections';

查询当前连接数

show status like 'max_used_connections';

临时设置最大链接数（mysql重启后失效）

set GLOBAL max_connections=5000;

查看mysql状态

show variables like '%connect%';

mysql配置文件，设置为永久：

修改  my.conf 配置文件

max_connections=5000  #支持的最大连接数，可调整