MySQL scheduled backup restore

mysql database - Backup and restore

Backup

mysqldump Command backup data

stay MySQL Using the command line... Is provided in , A convenient tool for exporting database data to files mysqldump , We can directly export the database content through the command line .

First of all, let's have a brief understanding of mysqldump Command usage :

# MySQLdump Commonly used 
/usr/local/mysql/bin/mysqldump -u xx -p databases > /xxx/xxxdb.sql

• mysqldump : mysql After installation bin The executable file in the directory
• -u ：mysql user name
• -p ：mysql password
• databases ： Database name
• ">" : Direction of backup output
• /xxx/xxxdb.sql ： Indicates which file to back up to

Be careful ： Backing up multiple databases , Need to use "--databases" Parameters , Later, according to the database name , Use spaces to separate .

mysqldump -uroot -proot --databases db1 db2 > /xxx/xxxdb.sql

mysqldump Common operation examples

1. Back up the data and structure of all databases

mysqldump -uroot -p123456 -A > /data/mysqlDump/mydb.sql

2. Back up the structure of all databases （ Add -d Parameters ）

mysqldump -uroot -p123456 -A -d > /data/mysqlDump/mydb.sql

3. Back up all database data ( Add -t Parameters )

mysqldump -uroot -p123456 -A -t > /data/mysqlDump/mydb.sql

4. Back up a single database " take -A Replace The corresponding database name ". Be careful ： -d -t The effect is the same .

mysqldump -uroot-p123456 mydb > /data/mysqlDump/mydb.sql

5. Backing up multiple databases

mysqldump -uroot -p123456 --databases db1 db2 > /data/mysqlDump/mydb.sql

Restore

Restore MySQL Backup content

There are two ways to restore ：

​ First use mysql Service command restore ：

• On the system command line , Enter the following to restore ：

mysql -uroot -proot databases < /xxx/xxxdb.sql

mysql ： The command means mysql The service procedure of

Be careful ：-u -p databases Same meaning as backup .

​ Second use sql Command restore ：

• Log in mysql In the library , adopt source Command to find the file in the corresponding system to restore ：

mysql> source /xxx/xxxdb.sql

source ： Database restore command

/xxx/xxxdb.sql : Represents the restored backup file

​ The third kind of full database restore ：

mysql -uroot -proot< /xxx/xxxdb.sql

Be careful ：xxxdb.sql The file must be the backup file of all databases

To write mysql Database backup script

1. Create script file

stay Linux in , Use vi perhaps vim Write the script and name it ：mysql_dump_script.sh

example ： This document is prepared according to my own needs mysql Script .（ Please modify it by yourself according to the situation ）

#!/bin/bash

# Save the number of backup , Backup 31 Day data 
number=31
# Backup save path 
backup_dir=/back
# date 
dd=`date +%Y-%m-%d-%H-%M-%S`
# Backup tools 
tool=/usr/local/mysql/bin/mysqldump
# user name 
username=root
# password 
password=root
# The database to be backed up 
database_name=jn-dev

# If the folder does not exist, create 
if [ ! -d $backup_dir ];
then     
    mkdir -p $backup_dir;
fi

# Database backup command  -  Simple writing  mysqldump -u root -p123456 users > /root/mysqlbackup/users-$filename.sql
$tool -u $username -p$password $database_name > $backup_dir/$database_name-$dd.sql

# Write create backup log 
echo "create $backup_dir/$database_name-$dd.dupm" >> $backup_dir/log.txt

# Find the backup that needs to be deleted 
delfile=`ls -l -crt $backup_dir/*.sql | awk '{print $9 }' | head -1`

# Determine whether the current number of backups is greater than $number
count=`ls -l -crt $backup_dir/*.sql | awk '{print $9 }' | wc -l`

if [ $count -gt $number ]
then
  # Delete the earliest generated backup , Only keep number Number of backups 
  rm $delfile
  # Write delete file log 
  echo "delete $delfile" >> $backup_dir/log.txt
fi

The main meaning of the above code is as follows ：

1. First, set the parameters , for example number The maximum number of backups required , Backup path , user name , Password etc. .

2. perform mysqldump Command save backup file , And print the operation to log.txt Mark the operation log in .

3. Define files to delete ： adopt ls Command to get the ninth column , That is, the list of documents , Then define the file to be deleted with the latest operation time through the implementation .

4. Define the number of backups ： adopt ls Command plus wc -l Statistics to sql The number of lines in the ending file .

5. If the file exceeds the limit size , Delete the first sql file

2. Set the execution permission of the script

Execute in the directory where the script file exists

chmod u+x *.sh

chmod Detailed explanation

chmod： file / Directory permission setting command

Use a text setting method that contains letters and operator expressions

Its grammatical form is ：chmod [who] [opt] [mode] file / Directory name

chmod u+x *.sh

• who Representative object , Is one or a combination of the following letters ：

  u：User, The owner of a file or directory .
  g：Group, That is, the group of files or directories .
  o：Other, Except for the owner or group of files or directories , Other users are in this range .
  a：All, All users , Include the owner , Group and other users .

• opt It represents operation , It can be for ：
  +： Add a permission
  -： Cancel a permission
  =： Give given permission , And cancel the original permission

• mode It means authority ：
  r： Can be read
  w： Can write
  x： Executable

• Symbol ：

​ "*"： wildcard

Be careful ： To ensure the correctness of the script file, you can test .（ The following directory is written in the same level directory of the file ）

sh mysql_dump_script.sh

Use crontab Execute backup scripts on a regular basis

Price

1. stay Linux in , Periodic tasks are usually performed by cron This daemons will handle [ps -ef|grep cron]
2. cron Read one or more configuration files , These configuration files contain the command line and its call time
3. cron The configuration file for is called “crontab”, yes “cron table” Abbreviation
4. cron The service is started by default

crontab Use

crontab [-u username]　　　　// Omitting the user table indicates the operation of the current user crontab
    -e      ( Edit the sheet )
    -l      ( List the orders in the worksheet )
    -r      ( Delete the work )

cron service

• CentOS6 Upper cron command

service crond start // Start the service 
service crond stop // Close the service 
service crond restart // Restart the service 
service crond reload // service crond reload 
service crond status  // Check the status 

• CentOS7 Upper cron command

systemctl start crond.service  // Start the service 
systemctl stop crond.service  // Close the service 
systemctl restart crond.service  // Restart the service 
systemctl reload crond.service  // service crond reload 
systemctl status crond.service   // Check the status 

// perhaps 
crond start
crond stop
crond restart
crond reload
crond status

lock situation

error ：crond: can’t lock /var/run/crond.pid

rm -rf /var/run/crond.pid

crontab Use

crontab The order of is ： Time + action

Time ： From front to back is branch 、 when 、 Japan 、 month 、 Zhou Five kinds , Operators have ：

• "*" All numbers in the range

• "/" How many numbers are passed

• "-" from X To Z

• "," Hash numbers

action ： Specify task script .

/back/mysql_dump_script.sh

Be careful ：

• Use /etc/crontab When you file You need to add the user before the action .

• Time user / action >> Log address

Create a scheduled task

Use crontab There are two ways to create a scheduled task ：

The first one is ：crontab -e ( It is the periodic planning task of a user )

1. Carry out orders

crontab -e

2. After execution, a file will be opened , Add a scheduled task to the file .

*/5 * * * * /back/mysql_dump_script.sh >> /back/mysql_dump_script.log
<--mysql_dump_script.log  Log file for scheduled task execution -->
<--  Every five minutes -->

The second kind ：vi /etc/crontab (/etc/crontab It is the periodic task of the system )

1. Carry out orders

vi /etc/crontab

2. After execution, a file will be opened , Add a scheduled task to the file （ Be careful root Is the user ）.

*/5 * * * * root/back/mysql_dump_script.sh >> /back/mysql_dump_script.log
<--mysql_dump_script.log  Log file for scheduled task execution -->
<--  Every five minutes -->

/etc/crontab Document and crontab -e Command difference

• The format is different ：crontab -e And /etc/crontab The modified syntax format is different ,/etc/crontab More than a user Appoint
• crontab -e It's for users cron To design the , Any user can edit the task . It should be noted that ：crontab -e It's actually /usr/bin/crontab This executive file .
• /etc/crontab For the system cron To design the . If it is a routine task of the system , Edit to /etc/crontab Just file it , however /etc/crontab It's a plain text file , Only use root Edit this file as .

Be careful ： To modify and edit the files of the above two methods, you need to restart cron service

Cancel scheduled tasks

1. crontab -l Indicates that all scheduled tasks are listed

   crontab -l 
   

2. Cancel scheduled tasks

• cancel all crontab -r

  crontab -r
  

• Cancel a certain crontab -e The configuration file , Delete which row configuration to cancel

   crontab -e
  

mysql Common mistakes

mysql Service not started

mysqldump: Got error: 2002: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2) when trying to connect
 When trying to connect , Unable to access the socket ‘/tmp/mysql.sock’（2） Connect to local MySQL The server 

Password risk prompt

mysql: [Warning] Using a password on the command line interface can be insecure.
 Using passwords on the command line interface may not be secure .