James's BLOG

move file by date

find PATH_A -type f ! -newermt 2017-01-01 -exec mv {} PATH_B \;

SELinux 影響 MySQL 連結

MySQL local 連 remote 時,
要關閉 SELinux 或設定才能連線

PHP upgrade always breaks session folder permissions

PHP 升級後都會自動改成 session owner 回原本設定,
網路建議是為 owner 另建子資料夾對應, 下次就不會被更動.

user = nginx

; Set session path to a directory owned by process user
php_value[session.save_handler] = files
php_value[session.save_path] = /var/lib/php/nginx/session
php_value[soap.wsdl_cache_dir] = /var/lib/php/nginx/wsdlcache

ref: https://serverfault.com/questions/582483/php-upgrade-always-breaks-session-folder-permissions

MariaDB Max connect

參考
https://pjstrnad.com/mariadb-raise-number-of-connections/

The issue is that you can’t have more max_connections than open_files_limit.

Indication is at the log

Changed limits: max_open_files: 1024 max_connections: 214 table_cache: 400

So you got to /etc/my.cnf and under [mysqld] add

open_files_limit=12000
max_connections=10000

But it’s not enough. Because of the systemd there are some limits in starting the mysql server – it’s already started with mysql user.

So you need to go to /etc/security/limits.conf and add

mysql soft nofile 4096
mysql hard nofile 10240

Then settings for systemd

mkdir -p /etc/systemd/system/mariadb.service.d
vi /etc/systemd/system/mariadb.service.d/limits.conf

And then enter this to to the file:

[Service]
LimitNOFILE=infinity

that worked to me. After restart of the mysql by

systemctl daemon-reload

systemctl restart mariadb

I got the connections fixed:

mysql
MariaDB [(none)]> select @@max_connections;
+-------------------+
| @@max_connections |
+-------------------+
| 10000             |
+-------------------+
MariaDB [(none)]> SHOW VARIABLES LIKE 'open%';
+------------------+-------+
| Variable_name    | Value |
+------------------+-------+
| open_files_limit | 65536 |
+------------------+-------+

That’s all.

mysql binlog too large

檢查硬碟空間
df -h

檢查資料夾大小
du -sh /home/james/*

MySQL log 太大
設定
/etc/my.cnf

只保留七天的 Log
[mysqld]
expire-logs-days=7

重啟 mysql
systemctl restart mariadb

進入 mysql
mysql -u root -p

刷新 log
FLUSH LOGS;

檢查目前 log 在哪個位置
SHOW MASTER STATUS;

清除指定時間 log
PURGE BINARY LOGS BEFORE NOW();

或清指定的 log 檔
PURGE BINARY LOGS TO 'mysql-bin.000047';

MariaDB max_connections, table_open_cache stuck

copy my-hugh.cnf to /etc/my.cnf.d/

editing
/etc/sysctl.conf
fs.file-max = 2459688

editing
/etc/security/limits.conf
mysql soft nofile 4096
mysql hard nofile 4096

editing
/etc/my.cnf.d/my-hugh.cnf
max_connections=1024
max_user_connections=1024
table_open_cache = 4096
table_definition_cache = 4096
open_files_limit=4096

ref:
https://codepoets.co.uk/2015/mysql-max_connections-stuck-on-214/

http://blog.endpoint.com/2013/12/increasing-mysql-55-maxconnections-on.html