How to solve the problem that mysql cannot start in Pagoda Panel

The problem and solution of the Pagoda panel not being able to start

If mysql in your Pagoda cannot be started, please first check if there are any following configuration issues

1 . Is your 3306 port being occupied, causing mysql to fail to start?

2. Is it due to insufficient disk space? If none of these problems occur, continue reading.

Frequently Asked Questions:

1. Mysql cannot be started after it is installed or files are migrated.

2. Mysql cannot be started after abnormal shutdown.

3. Mysql cannot be started after it is stopped. Startup

1. Mysql cannot be started after it is installed or after migrating files

When Mysql has just been installed or cannot be started after migrating files, we generally first check whether the owner of the Mysql data directory is the mysql user.

For example, our pagoda environment is:

• Mysql data directory: /www/server/data

• Mysql program directory: /www/server/mysql

• Mysql main configuration file:/etc/my.cnf

## First check the hard disk partition usage Is it full? Execute the following command to check the partition capacity usage

df -h

Execute the following command to check the partition inode usage

df -i

Use the ll command to check the directory details

[root@test server]# ll /www/server/
total 24
drwxr-x---   6 root     root     4096 Oct 30 17:51 data
drwx--x--x  14 root     root      182 Oct 16 18:01 docker
drwxrwxr-x  12 root     root      326 Oct 24 18:06 mysql
drw-------. 14 root     root     4096 Oct 24 18:06 panel

You can see that the owner of the data directory is root. At this time, the error message when starting mysql is as follows

[root@test server]# /etc/init.d/mysqld start
Starting MySQL. ERROR! The server quit without updating PID file (/www/server/data/test.com.pid).

We first modify the owner of the directory to mysql

chown -R mysql.mysql data

Start the database

/etc/init.d/mysqld start

You can see that it has been started successfully

[root@test server]# /etc/init.d/mysqld startStarting MySQL... SUCCESS!

If it is not working yet check your selinux status

getenforce

If the return value is not valid disable

Run the command to temporarily stop selinux

setenforce 0

Try to start again

2. Mysql cannot be started after abnormal shutdown

Mysql is shut down abnormally, which is a situation we often encounter. When restarting the server, mysql is not shut down in advance, and the server is powered off. Using the kill command to kill the mysql process is an abnormal shutdown, and abnormal shutdown often brings some unpredictable consequences.

Under normal circumstances, abnormal shutdown will cause the binary log file to be damaged

Execution

rm -f /www/server/data/ib_logfile0
rm -f /www/server/data/ib_logfile1

Delete the log and try to start again

Encountered an errorAnother MySQL daemon already When running with the same unix socket

You can try to delete the sock file and then start again

rm -f /tmp/mysql.sock*
rm -f /tmp/mysqlx.sock*

When you encounter an error [ERROR] InnoDB: Cannot allocate memory for the buffer pool

Indicates that the current memory required for mysql startup is not enough. We need to adjust the memory of

innodb_buffer_pool_size
key_buffer_size

3. Mysql cannot be started after it is stopped

The reason why Mysql cannot be started after it is stopped normally

1. It shows that the stop is successful but the actual stop fails. There are residual processes. We can use ps to check

ps -ef|grep mysql

2. The disk space is full and mysql cannot be started.

3. Sometimes manually Deleting the binlog log and restarting mysql will also cause the failure to start. You can find the words

File ‘./mysql-bin.000001’ not found in the error log. Solution:

Comment the configuration of the main configuration file

Find

log-bin=mysql-bin

Change to

#log-bin=mysql-bin

Or clear

mysql-bin.index

The following two solutions are: You can choose to try 1 according to your own situation. Solve it by changing etc/init.d/mysqld

Then there is another way that I personally solve this problem by checking posts. First

1. The first step First find the file etc/init.d/mysqld and then open it and find the start part

Just open the string of codes without the blue box, add it and save it Close

2. Open the pagoda terminal and directly enter the line of code service mysqld start to let mysql run

3. Then look at mysql and it has started running

2 Solved by deleting a file

Some mysql that cannot be started may be that the master-slave replication has not been started, but there is an extra mysql-bin.index file inexplicably under /www/server/data. At this time, Deleting this file and then starting it again can also start successfully, but mine does not work with this. You can choose a solution according to your own situation

Finally, I have to say not to restart or shut down mysql when adjusting its performance. It’s easy to make mistakes

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