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MySQL Backup

MySQL Backup
Hostman Team
Technical writer
MySQL
21.12.2023
Reading time: 6 min

In this article, we will consider ways of backing up MySQL DBMS and give examples of the most useful keys and parameters. You can use Hostman cloud databases as a test platform.

Syntax

You can create a database dump through the command line using the mysqldump utility. It is installed by default with the MySQL package. Its functionality is the same on Linux and Windows, and it can be launched on both local and remote DBMS servers. General syntax:

mysqldump [options] > <dump_file_name>

Example:   

mysqldump -v -h127.0.0.0.1 -uroot mydb -p > /tmp/dump.sql

Here, we have made a backup archive of the database called mydb and placed it in the /tmp directory. We connect to the local database (IP 127.0.0.1) under the root account. It is the simplest way of creating a MySQL database backup. 

These are the basic parameters of the mysqldump utility:

  • -h is the host address you must connect to to create the dump.

  • -u is the account that performs the backup (make sure that you have all the necessary permissions).

  • -p is the account password. When using a script, it should be entered in the format p12345; in other cases, it is better to leave only the -p symbol, as it is safer.

We have listed only the most popular parameters. Check the official website to view the full list for a more in-depth study of the issue. 

Creating MySQL dumps

Let's look at several other cases. 

Backing up with subsequent archiving

Command:

DBNAME=mydb
mysqldump -uroot -p ${DBNAME} | gzip -c > /tmp/${DBNAME}.sql.gz

We made a DBNAME variable and placed the name of the database we need to archive. After that, we ran the mysqldump utility to pass the execution queue to the GZIP archiver upon completion. 

As a result, the dump is placed in the /tmp/<base name>.sql.gz directory. If you want to display the process on the screen, use an additional -v option:

mysqldump -v -uroot -p ${DBNAME} | gzip -c > /tmp/${DBNAME}.sql.gz

Simultaneous archiving of two or more databases

The task is simple, just list the database names with a space and use the -B option. This is how the command will look like:

mysqldump -v -uroot -p -B base1 base2 base3 > /tmp/dump_multiplе_bases.sql

Backing up all available bases

You can also run MySQL database backups using the --all-databases parameter instead of the database name. Example command: 

mysqldump -v -uroot -p --all-databases > /tmp/dump_all_bases.sql

Backing up only the database structure

This method will save the tables without any data to the archive. The mode is selected using the --no-data parameter:

mysqldump -v -uroot -p --no-data base1 > /tmp/dump_base1_nodata.sql

Backing up a table

In this case, you should add the table name to the database name. For example, as in the command:

mysqldump -v -uroot -p base1 table1 table2 > /tmp/dump_base1_tables.sql

Transferring DBMS access rights

The system can unload the current accounts along with the current passwords. This function is required to export the DBMS to another host without the risk of losing access to the database. The command will look like this:

mysqldump -v -uroot -p mysql user > /tmp/mysql_user.sql

Execute the flush privileges command (via SQL Shell) to ensure operability after migration.

Ignoring a specific table during archiving

Use the command with the --ignore-table key:

mysqldump -v -uroot -p base --ignore-table=base.logs > /tmp/base.sql

Backing up under any account

In the examples above we connect to the database as the root user. In practice, the procedure can be performed under other accounts as well. The main thing is that the selected user should have the right to access the database we need to dump. You can create a separate account with limited rights to perform archiving. Let's do it with the SQL command:

> GRANT SELECT, SHOW VIEW, RELOAD, REPLICATION CLIENT, EVENT, TRIGGER, LOCK TABLES, PROCESS, EXECUTE ON *.* TO backup@localhost IDENTIFIED BY 'backup123';

Here, we have created the backup account and set its password as backup123. The user will have access to connect to the database on the local server. In order not to manually enter the same parameters at each startup, we can write a configuration file:

vi ~/.my.cnf 
[mysqldump]
host = 127.0.0.1
user=backup
password="backup123"

Now, the command will take a "light" form:

mysqldump base > /tmp/dump.sql

Backing up the database via phpMyAdmin

If it is inconvenient to work in the console, you can use phpMyAdmin. 

Go to the "Export" item of the top menu, and in the "Export Method" section, put the switch to "Normal". After that, several additional options will open. Among them, we are interested in the compression method, for example, ZIP. Click OK, and the dump will be downloaded, backed up, and saved on the local computer.

Troubleshooting

Sometimes, you may encounter the error Incorrect key file for table, which looks like this:

mysqldump: Error 1034: Incorrect key file for table '<table name>'; try to repair it when dumping table `<table name>` at row: xxxxxx

There may be several reasons for this. For example, a logical error of a table in the database has been detected, or the storage space where the system saves temporary data has run out. Accordingly, different approaches are needed to solve the problem. So, the first thing to do is to check the amount of space on the disk. The configuration file located at /etc/my.cnf contains the tmpdir option, which defines the folder where the system saves temporary tables.

If it does not exist, the /tmp path will be used by default. You can check if there is enough space to create a dump with the command:

df -h

The situation is different if a table is corrupted. It must be restored, but the solution depends on the type of the problematic part of the database.

MyISAM. In the SQL command line, enter the command:

> REPAIR TABLE <table name> USE_FRM;

After that, repeat the attempt to create a backup copy.

INNODB. Open the DBMS configuration file:

vi /etc/my.cnf

Find the [mysqld] section and add the line:

innodb_force_recovery = 1

Restart the database server:

systemctl restart mysql

If the error occurs again, change the value of innodb_force_recovery to 2. If the problem persists, change it to 3, and so on up to 6, until the backup succeeds. Keep in mind that the applied parameter sometimes leads to data loss. If you have to raise its value above 2, you should manually check if valuable information is still safe after the backup is completed.

Conclusion

The mysqldump command has a wide functionality that allows you to backup databases in various combinations. If necessary, it can be easily replaced by phpMyAdmin, a convenient tool with a graphical interface. To experiment with these instructions, use a test database, with no valuable information. For example, you can rent a cloud database from Hostman.

MySQL
21.12.2023
Reading time: 6 min

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MySQL

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How to Create a MySQL Database Dump

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Alternatively, you can list the databases you want to include in the dump: mysqldump -u admin -p'qwerty123' -h 91.206.179.29 -P 3306 db_first db_second db_third --no-tablespaces --set-gtid-purged=OFF --single-transaction > just_dump.sql Structure Without Data You can create a dump containing only the database structure (table schemas) without any data by using the --no-data flag: mysqldump -u admin -p'qwerty123' -h 91.206.179.29 -P 3306 default_db --no-data --no-tablespaces --set-gtid-purged=OFF --single-transaction > just_dump.sql Specific Tables Instead of dumping an entire MySQL database, you can dump only specific tables by listing their names after the database name: mysqldump -u admin -p'qwerty123' -h 91.206.179.29 -P 3306 default_db table1 table2 --no-data --no-tablespaces --set-gtid-purged=OFF --single-transaction > just_dump.sql On the other hand, you can dump a database excluding specific tables using the --ignore-table parameter: mysqldump -u admin -p'qwerty123' -h 91.206.179.29 -P 3306 default_db --ignore-table=default_db.logs --no-data --no-tablespaces --set-gtid-purged=OFF --single-transaction > just_dump.sql Note that the table name must always be preceded by the database name and separated by a dot. 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It will take you to a dedicated page to configure the database export (dump). You can also access the export page from the phpMyAdmin home page, but doing so may not display all databases available for export. It's better to first navigate to the specific database and then click Export. Note that phpMyAdmin allows exporting only databases that contain tables. Empty databases cannot be exported. There are two export options in phpMyAdmin: Quick Export. It creates the dump using default export settings. Custom Export. It Allows you to manually configure the export settings, such as excluding specific tables, changing character encoding, and adjusting format options. phpMyAdmin supports exporting to various formats beyond just SQL, such as PDF, JSON, CSV, YAML, and others. The configuration options for creating a dump in phpMyAdmin are more user-friendly and visually intuitive than command-line flags. 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13 February 2025 · 12 min to read
MySQL

How to Import and Export Databases in MySQL or MariaDB

Database management is a crucial aspect of Linux server and web application administration. Importing and exporting databases are essential tasks for DevOps and system administrators. At a minimum, developers should know how to back up databases and transfer them between servers. This guide explains how to import and export database dumps in MySQL or MariaDB on a Linux server (using Ubuntu as an example). Working with Databases MySQL and MariaDB are popular relational database management systems (RDBMS) used for storing data in large applications. MariaDB is a fork of MySQL developed by its original creators due to licensing concerns following Oracle's acquisition of MySQL. Both MariaDB and MySQL share identical or similar APIs and operating mechanisms. Creating a Database Connect to MySQL or MariaDB with root privileges: For MySQL: mysql -u root -p   For MariaDB: mariadb -u root -p   Create a database (if it doesn't already exist): CREATE DATABASE IF NOT EXISTS <database_name>; Viewing Databases To see the list of available databases: SHOW DATABASES; Switching Databases To switch to a specific database: USE <database_name>; Viewing Tables To list all tables in the selected database: SHOW TABLES; Common SQL Commands Creating a table: CREATE TABLE IF NOT EXISTS users (  user_id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,  username VARCHAR(100) NOT NULL); This creates a table named users with fields user_id and username. Inserting data into the table: INSERT INTO users (username) VALUES ('John Doe'); This adds a new row to the users table. Selecting all rows from the table: SELECT * FROM users; Monitoring MySQL/MariaDB status To check the server's global status and statistics: SHOW GLOBAL STATUS; Exporting Databases Exporting data from MySQL or MariaDB can be efficiently done using the mysqldump CLI utility or third-party tools like phpMyAdmin. The mysqldump utility allows you to save your database as an SQL dump, which contains the necessary commands for creating columns and populating them with data. This dump file can be easily managed, imported, or transferred. You will need: A database you want to export. User credentials with at least read access to the database. In the terminal, run the following command: mysqldump -u <username> -p<password> <database_name> > db_dump.SQL Where: -p<password>: Password for the database user (you can omit the password and simply use -p to prompt for it manually). db_dump.SQL: The name of the output dump file. <username>: The privileged user with read access. <database_name>: The name of the database you are exporting. To create dumps from a remote server, add the -h flag: mysqldump -h <ip-address> -u <username> -p<password> <database_name> > db_dump.SQL If the MySQL server uses a non-standard port, specify it with the -P flag: mysqldump -h <ip-address> -P <port> -u <username> -p<password> <database_name> > db_dump.SQL While the default export format is SQL, mysqldump also supports exporting data as CSV, XML, and other formats by configuring additional parameters. The SQL dump typically includes: Information about the RDBMS (MySQL or MariaDB) Commands for creating the required tables and their columns Data to populate those columns By default, it provides a comprehensive snapshot of the database structure and contents, making it an essential tool for database backups and migrations. Importing Data into MySQL or MariaDB To import a database dump, you don’t need mysqldump; a direct call to MySQL will suffice. Run the following command in your terminal: mysql -u <username> -p<password> <new_database_name> < db_dump.SQL Where: -p<password>: The user's password (use -p without the password to be prompted manually). db_dump.SQL: The dump file containing your database data. <username>: A privileged user with write access. <new_database_name>: The name of the target database to which you are importing the dump. If the process completes successfully, there will be no output. If any errors or warnings occur, MySQL or MariaDB will display them. You can check if the import was successful with these commands: SHOW DATABASES;  -- Lists all databasesUSE <database_name>;  -- Selects the target databaseSHOW TABLES;  -- Lists all tables within the selected database By executing these commands, you can confirm that the database structure and data have been imported correctly. Creating a systemd Service for Backup Suppose you want to automate the database backup (export) process. In this guide, we will create a service-timer that will trigger a script for backing up data. A Timer is a mechanism used to schedule the execution of a specific service at a given time or through certain intervals. Follow these steps to set it up: First, connect to the server and create the directory for backup scripts: mkdir -p /usr/bin/backup_scripts  # Create directory for backup scripts Create and open the file /usr/bin/backup_scripts/mysql_backup.sh in any text editor (e.g., nano): nano /usr/bin/backup_scripts/mysql_backup.sh Inside the file, add the following script: TIMESTAMP=$(date +'%F') # Get the current date BACKUP_DIR='<path_to_backup_directory>' MYSQL_USER='<username>' MYSQL_PASSWORD='<password>' DATABASE_NAME='<database_name>' mkdir -p "$BACKUP_DIR/$TIMESTAMP" # Create directory for this date mysqldump -u $MYSQL_USER -p$MYSQL_PASSWORD $DATABASE_NAME > "$BACKUP_DIR/$TIMESTAMP/$DATABASE_NAME-$TIMESTAMP.sql" # Create dump find "$BACKUP_DIR" -type d -mtime +28 -exec rm -rf {} \; # Delete backups older than 28 days Replace the placeholder variables with the actual backup directory path, MySQL user credentials, and the database name. Grant execution permissions to the script: chmod +x /usr/bin/backup_scripts/mysql_backup.sh Create the service file /etc/systemd/system/mysql-backup.service: sudo nano /etc/systemd/system/mysql-backup.service Add the following content: [Unit] Description=MySQL Database Backup Service [Service] Type=oneshot ExecStart=/usr/bin/backup_scripts/mysql_backup.sh [Install] WantedBy=multi-user.target Create the timer file: sudo nano /etc/systemd/system/mysql-backup.timer Add this content to schedule the backup: [Unit] Description=Run MySQL Backup Service Weekly [Timer] OnCalendar=weekly Persistent=true [Install] WantedBy=timers.target Reload the systemd configuration, enable the timer for autostart, and start it: systemctl daemon-reload  # Reload systemd configurationsystemctl enable mysql-backup.timer  # Enable timer to start automaticallysystemctl start mysql-backup.timer  # Start the timer Check the status of the timer and ensure it is working: systemctl status mysql-backup.timersystemctl list-timers  # Lists active timers Now, your system will automatically create a backup of the specified database every week. Export and Import via phpMyAdmin You can perform database imports and exports not only through command-line utilities but also through the phpMyAdmin web interface. This method is typically more convenient when the dump size is small (less than 1GB). This section will cover the basic process of importing and exporting databases. Export To export a database: Go to the phpMyAdmin interface and select the desired database from the left-hand panel. Click on the Export tab. Choose export method: Quick Export: Select this if you want a basic export with default settings. Custom Export: Choose this for more specific export options, such as selecting certain tables, formats, or compression methods. Click Export. To export specific tables: Click on the database name in the left sidebar to view its tables. Select the tables you want to export by checking the boxes next to their names. At the bottom of the page, choose Export from the list of actions. On the next page, verify the export format and options, then click Go to save the dump to your local machine. Import The process of importing a database is very similar to exporting. Follow these steps: Open phpMyAdmin and navigate to the database you want to import into. If the database doesn't exist, create it by clicking Create Database from the left sidebar. Inside the database, click on the Import tab. Click the Choose File button to browse for and select the SQL dump file from your device. Choose the necessary options like file encoding, format (typically default settings are fine), and other options as needed. Click Go to start the import process. Once the process is complete, you will see the imported files and their contents listed in the left sidebar. You can also modify them if needed. Conclusion The choice of method depends on your needs: phpMyAdmin is ideal for manually creating backups or for quick access to a database. It’s user-friendly and simple for small-scale tasks. Using command-line utilities would be more efficient and flexible for automation or if you’re transferring infrastructure.
10 February 2025 · 8 min to read

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