MySQL backup and recovery + experiment

mysql Backup and recovery of

The importance of data backup

The main purpose of backup is disaster recovery

In the production environment , Data security is crucial

Any loss of data can have serious consequences

Cause of data loss

Program error

Human error

Arithmetic error

Disk failure

disaster ( Such as fire 、 The earthquake ) And theft

From the point of view of physics and logic , Backup can be divided into

The physical backup : Physical files for database operating system ( Such as data files 、 Log files, etc ) Backup of

Physical backup method

Cold backup ( Offline backup ) : It was done when the database was shut down

Hot backup ( Online backup ) : The database is running , Database dependent log files

Warm backup : Database lock table ( Not writable but readable ) Backup operation in the state of

Logical backup : For database logic components ( Such as : Database objects such as tables ) Backup of

From the perspective of database backup strategy , Backup can be divided into ：

Full backup : Every time you make a full backup of the database

Differential backup : Back up files that have been modified since the last full backup

Incremental backup : Only files modified after the last full backup or incremental backup will be backed up

Common backup methods

Physical cold standby

The database is closed at the time of backup , Directly package database files

Fast backup , Recovery is also the simplest

Special backup tool mydump or mysqlhotcopy

mysqldump Common logical backup tools

mysqlhotcopy Only have Backup MyISAM and ARCHIVE surface

Enable two - Perform incremental backup of hexadecimal logs

Incremental backup , Need to refresh binary log

Third party tools backup

Free of charge MySQL Hot backup software Percona XtraBackup

MySQL Full backup ( Definition )

■ For the entire database 、 Backup of database structure and file structure

■ What you save is the database at the time of backup completion

■ The difference between backup and incremental backup is

Physical cold backup and recovery

close MySQL database

Use tar Command to package the database folder directly

Replace existing directly MySQL directory

mysqldump Backup and recovery

MySQL Backup tools included , It is convenient to realize MySQL Backup of

You can add the specified library 、 The table is exported as SQL Script

Use command mysq| Import backup data

Back up the database completely

Case study 1： First create a database

Log in and copy

use kgc;

create table if not exists info1 (

id int(4) not null auto_increment,

name varchar(10) not null,

sex char(10) not null,

hobby varchar (50) ,

primary key (id));


insert into info1 values(1,'user1','male',' running');
insert into info1 values(2,'user2','female','singing');


     

      
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mysql Full backup of

InnoDB The database of the storage engine is stored in three files on disk : db.opt ( Table properties file )、 Table name . frm( Table structure file )、 Table name .ibd( Table data file ).

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1. Physical cold backup and recovery 

systemctl stop mysqld

yum -y install xz   # Compressed backup 

tar jcvf /opt/mysql_all_$(date +%F) .tar.xz /usr/local/mysql/data/

# Decompression recovery 
tar Jxvf /opt/mysql_all_2020-11-22.tar.xz -C /usr/local/mysql/data


2. mysqldump  Backup and recovery 

(1) Full backup of one or more complete libraries ( Including all the tables )

mysqldump -u root -p[ password ] --databases  Library name 1 [ Library name 2] ... > / Backup path / Backup filename .sql        # What is exported is the database script file 
 give an example ：
mysqldump -u root -p --databases kgc > /opt/kgc.sql
mysq1dump -u root -P --databases mysql kgc > /opt/mysq1-kgc.sql

(2) Full backup MySQL All libraries in the server 
mysqldump -u root -p [ password ] --all-databases > /  Backup path / Backup filename .sql
 example :
mysqldump -u root -P --all-databases > /opt/all.sql

(3) Full backup of some tables in the specified library 
mysqldump -u root -p[ password ] Library name [ Table name 1] [ Table name 2] ... > / Backup path / Backup filename .sq1
 give an example ：
mysqldump -u root -p [-d] kgc info1 info2 ... > /opt/kgc_info1.sql
# Use “-d” Options , Note: only the table structure of the database is saved 
# Don't use “-d” Options , Note that table data is also backed up 

(4) View backup files 
grep -V "^--" /opt/kgc_info1.sql | grep -v "^/" | grep -v "^$"


     

      
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mysql A complete recovery of

systemctl start mysqld

(1) Recover database

mysql -u root -p -e 'drop database kgc; ’

#“-e” Options , Used to specify the connection MySQL Command executed after , Automatically exit after the command is executed

mysql -u root -P -e 'SHOW DATABASES; ’

mysql -u root -p < /opt/kgc.sql

(2) Restore data table

When the backup file contains only the backup of tables , Without the statement of the created library , The library name must be specified when performing the import operation , And the target library must exist .

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mysqldump -u root -P kgc info1 >         /opt/kgc_info1.sql
 
mysql -u root -P -e 'drop table kgc. info1; '



mysql -u root -P kgc < /opt/kgc_info1.sql

mysql -u root -P -e ' show tables from kgc; '

     

      
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mysql Incremental logging and recovery

----MySQL Incremental backup ----

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mysqladmin -u root -p flush-logs
1. Turn on binary log function 
vim /etc/my.cnf
[mysq1d]
log-bin=mysql-bin
binlog_format = MIXED  # Optional , Specify binary log (binlog) The record format of is MIXED
server-id = 1
# Binary log (binlog) Yes 3 Two different record formats : STATEMENT ( be based on SQL sentence )、ROW( Based on line )、MIXED( Mixed mode ),  The default format is STATEMENT

systemctl start mysqld
ls -l /usr/local/mysql/data/mysql-bin.*    # Check whether it is recognized , Otherwise it won't work mysqldump！

2. The database or table can be fully backed up every week 
mysqldump -u root -p kgc info1 > /opt/kgc_ info1_$(date +%F).sql
mysqldump -u root -P --databases kgc > /opt/kgc_ $(date +%F).sql

3. Incremental backup operations can be performed every day , Generate a new binary log file ( for example mysql-bin.00002)
mysqladmin -u root -P flush-logs

4. Insert new data , To simulate the addition or change of data 
use kgc;
insert into info1 values (3,'user3','male', 'game');
insert into infol values (4,'user4','female', 'reading');

5. Generate a new binary log file again ( for example mysql-bin.00003)
mysqladmin -u root -p flush-logs
# Previous steps 4 The database operation will be saved to mysql-bin.00002 In file , After that, if the database data changes again, it is saved in mysql-bin.000003 In file 

6. View the contents of the binary log file 
cp /usr/local/mysql/data/mysql-bin.000002 /opt/
mysqlbinlog --no-defaults --base64-output=decode-rows -v /opt/mysql-bin.000002
#--base64-output=decode- rows: Use 64 Bit encoding mechanism to decode and read by line 
#-V: Show details 

     

      
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mysql Incremental recovery of

Log in and copy

1. General recovery 

(1) Simulate recovery steps for lost changed data 
use kgc;
delete from info1 where id=3;
delete from info1 where id=4;

mysqlbinlog --no-defaults /opt/mysql-bin.000002 | mysql -u root -p

(2) Simulate recovery steps for all lost data 
use kgc;
drop table info1; 

mysql -u root -p kgc < /opt/kgc_info1_2022-02-13.sql
mysqlbinlog --no-defaults /opt/mysql-bin.000002 | mysql -u root -P


2. Breakpoint recovery 
mysqlbinlog --no-defaults --base64-output=decode-rows -v /opt/mysql-bin.000002
 give an example ：
# at 302
#20112216:41:16
 Inserted "user3" User data for 


# at 623
#20112216:41:24
 Inserted "user4" User data for 

(1) Based on location recovery 

# Restore to operation only ID by “623" Previous data , I.e. no recovery "user4" The data of 
mysqlbinlog --no-defaults --stop-position='623' /opt/mysql-bin.000002 | mysql -uroot -P


# Restore only "user4" The data of , skip "user3" Data recovery 
mysqlbinlog --no-defaults --start-position=' 623' /opt/mysql-bin.000002 | mysql -uroot -P

(2) Based on point in time recovery 
# Only restore to 16:41:24  Previous data , I.e. no recovery "user4" The data of 
mysqlbinlog --no-defaults --stop-datetime= '2020-11-22 16:41:24' /opt/mysql-bin.000002 lmysql -uroot -P

# Restore only "user4" The data of , skip "user3" Data recovery 
mysqlbinlog --no-defaults --start-datetime= ' 2020-11-22 16:41:24' /opt/mysql-bin.000002 lmysql -uroot -p

 summary ：
 If you restore a SQL All data before the statement , Just stop At the position node or point in time of this statement 
 If you restore a SQL Statement and all subsequent data , From the position node or time point of this statement start


     

      
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