No space left on device in server | PHPMysql not connect session | Full Inodes 100% | Check CPU Process and MEMORY

Issues

1. open(/var/lib/php/sessions/sess_, O_RDWR) failed: No space left on device (28)
2. PHPMysql not connect
3. Database not connect

Solusions

Check CPU and MEMORY usage of server from terminal

ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%cpu | head

df -h

Check file size

find /home/ -size +100M 

 

 Check INODES in server (Inode mean total files into server)

df -i

Search INODES from system and perticular folder (Get number of file in perticular directory)

for i in /var/www/html/*; do echo $i; find $i |wc -l; done

Check INODES into specific directory

ls -l /var/lib/php/sessions | wc -l

Remove all files from specific directory

rm -r /var/lib/php/sessions/ 

If you are using PHP so you can create code in any existing file

$path = '/var/lib/php/sessions/';
$dir = opendir($path);
$i = 0;
while ($dir && ($file = readdir($dir)) !== false) {
    unlink($path.$file);
    echo $i.' - '.$path.$file.'<br>';
    if($i == 50000){
        exit;
    }
    $i++;
}

How to reset MySQL / phpmyadmin root password on Ubuntu 18.04 Linux

1. The simplest approach to reset MySQL database root password is to execute mysql_secure_installation program and when prompted entering your new root MySQL password:

sudo mysql_secure_installation

New password:
Re-enter new password:

2. Let's stop the currently running MySQL database:

sudo service mysql stop

3. create a /var/run/mysqld directory to be used by MySQL process to store and access socket file:

sudo mkdir -p /var/run/mysqld
sudo chown mysql:mysql /var/run/mysqld 

4. Start manually MySQL with the following linux commands :

sudo /usr/sbin/mysqld --skip-grant-tables --skip-networking &

5. Confirm that the process is running as expected: 

jobs

6. Access MySQL database without password 

mysql -u root

7. First flush privileges MySQL session

mysql> FLUSH PRIVILEGES;

8. The following commands will reset MySQL root password to "root" 

mysql> USE mysql;
mysql> UPDATE user SET authentication_string=PASSWORD("root") WHERE User='root';
mysql> UPDATE user SET plugin="mysql_native_password" WHERE User='root';

9. Exit MySQL session: 

mysql> exit

10. Terminate current mysqld process 

sudo pkill mysqld

11. Start MYSQL database:

sudo service mysql start

12. If all went well you should now be able to login to your MySQL database with a root password: 

mysql -u root --password=root
mysql> exit