先做个简单记录，后面有时间再编辑
应用报错

java.sql.SQLException: Out of resources when opening file '.MYD' (Errcode: 24 - Too many open files)

检查方法

mysql> show global variables like "%open%";
+----------------------------+----------+
| Variable_name              | Value    |
+----------------------------+----------+
| have_openssl               | DISABLED |
| innodb_open_files          | 3000     |
| open_files_limit           | 2000    |
| table_open_cache           | 2000     |
| table_open_cache_instances | 16       |
+----------------------------+----------+
5 rows in set (0.00 sec)

系统层面

df -h 
df -i
ulimit -n
cat /etc/security/limits.conf

参考

https://forums.cpanel.net/threads/out-of-resources-when-opening-file-tmp-sql_26b7_0-myi-errcode-24.419342/