Mysql daily backup and incremental backup script

Suitable objects

This article was tested under Linux, mysql 4.1.14 version. After appropriate modification, it may be suitable for mysql 4.0, 5.0 and other versions.

This article is suitable for mysql that does not have the replication function enabled. If replication is enabled , it may not be necessary to adopt this backup strategy or to modify relevant parameters.

Everyone’s backup strategy may be different, so please modify it according to the actual situation and draw inferences from one example. Do not copy it as it may cause unnecessary losses.

Hope you understand what this script does!

Script description

Back up all data every 7 days, and back up binlog every day, which is an incremental backup.

(If there is less data, just back up the complete data once a day, There may be no need to do incremental backup)

The author is not very familiar with shell scripts, so many places are written very stupidly:)

Enable bin log

In mysql version 4.1, by default there is only error log and no other logs. You can open the bin log by modifying the configuration. There are many ways, one of which is to add the mysqld section in /etc/my.cnf:

[mysqld]
log-bin

The main function of this log is incremental backup or replication ( There may be other uses).

If you want incremental backup, you must open this log.

For mysql with frequent database operations, this log will become very large, and there may be multiple.

flush in the database -logs, or use mysqladmin, mysqldump to call flush-logs and use the parameter delete-master-logs, these log files will disappear and new log files will be generated (empty at first).

So if you have never backed up, enable it Logs may not be necessary.

You can call flush-logs at the same time as the full backup, and flush-logs before the incremental backup to back up the latest data.

Full backup script

If the database has a lot of data, we usually take a few days Or back up the data once a week to avoid affecting application operation. If the amount of data is relatively small, then it doesn’t matter if you back up the data once a day.

#!/bin/sh

# mysql data backup script
# by scud http://www. jscud.com
# 2005-10-30
#
# use mysqldump --help,get more detail.
#

BakDir=/backup/mysql
LogFile=/backup/mysql/mysqlbak.log

DATE=` date +%Y%m%d`

echo " " >> $LogFile
echo " " >> $LogFile
echo "----------------- --------------------------" >> $LogFile
echo $(date +"%y-%m-%d %H :%M:%S") >> $LogFile
echo "--------------------------" >> $LogFile

cd $BakDir

DumpFile=$DATE.sql
GZDumpFile=$DATE.sql.tgz

mysqldump --quick --all-databases --flush-logs
--delete-master-logs --lock -all-tables
> $DumpFile

echo "Dump Done" >> $LogFile

tar czvf $GZDumpFile $DumpFile >> $LogFile 2>&1

echo "[$GZDumpFile]Backup Success! " >> $LogFile

rm -f $DumpFile

#delete previous daily backup files: Files that are incrementally backed up. If the files are backed up completely, the incremental backup files will be deleted.
cd $BakDir/daily

rm -f *

cd $BakDir

echo "Backup Done!"

echo "please Check $BakDir Directory!"

echo "copy it to your local disk or ftp to somewhere !!!"

ls -al $BakDir
The above script backs up mysql to the local /backup/mysql directory, and the incremental backup files are placed in the /backup/mysql/daily directory.

Note: The above script does not save the backed up files Transferred to other remote computers, the backup files from a few days ago are not deleted: the user needs to add relevant scripts or perform manual operations.

Incremental backup

The amount of data in incremental backup is relatively small, but it must be based on the full backup Users can weigh time and cost and choose the method that is most beneficial to themselves.

Incremental backup uses bin log, the script is as follows:

#!/bin/sh

#
# mysql binlog backup script
#

/usr/bin/mysqladmin flush-logs

DATADIR=/var/lib/mysql
BAKDIR=/backup/mysql/daily

###If you have made special settings, please modify here Or modify the line that applies this variable: the default is to take the machine name, and mysql also takes the machine name by default
HOSTNAME=`uname -n`

cd $DATADIR

FILELIST=`cat $HOSTNAME-bin.index`

# #Calculate the number of lines, that is, the number of files
COUNTER=0
for file in $FILELIST
do
COUNTER=`expr $COUNTER + 1 `
done

NextNum=0
for file in $FILELIST
do
base=` basename $file`
NextNum=`expr $NextNum + 1`
if [ $NextNum -eq $COUNTER ]
then
echo "skip lastest"
else
dest=$BAKDIR/$base
if(test -e $dest )
then
echo "skip exist $base"
else
echo "copying $base"
cp $base $BAKDIR
fi
fi
done

echo "backup mysql binlog ok"
The incremental backup script is to flush-logs before backup. MySQL will automatically put the logs in the memory into the file and then generate a new log file, so we only need to backup the first few That’s it, that is, the last one is not backed up.
Because there may be multiple log files generated from the last backup to this backup, so the file needs to be detected. If it has been backed up, there is no need to back it up.

Note: Same , the user also needs to transmit it remotely by himself, but there is no need to delete it. The program will be automatically generated after a complete backup.

Access settings

The script has been written. In order to allow the script to run, the corresponding user name and password, mysqladmin and mysqldump, need to be set. They all require a username and password. Of course, they can be written in a script, but it is inconvenient to modify. Assuming that we use the root user of the system to run this script, then we need to create it in /root (that is, the home directory of the root user) A .my.cnf file with the following content

[mysqladmin]
password =password
user= root
[mysqldump]
user=root
password=password
Note: Set this file to be readable only by root. (chmod 600 .my.cnf )

This file explains that the program uses the root user of mysql to back up data, and the password is the corresponding setting. In this way, there is no need to write the user name and password in the script.

Automatically run

In order to make the backup program To run automatically, we need to add it to crontab.

There are two methods. One is to put the script into directories such as /etc/cron.daily and /etc/cron.weekly according to your own choice.
One is to Use crontab -e to put it into the scheduled tasks of the root user. For example, the full backup runs every Sunday at 3 am, and the daily backup runs every Monday to Saturday at 3 am.