Memory of 42

本文主要記錄下使用percona xtrabackup 2.4來備份mysql數據。最終效果是實現mysql所在主機定時進行全量備份和增量備份並自動刪除舊備份文件。另有一台數據存儲機，定時通過ssh抓取各個mysql主機上的備份文件，保存更長時間後刪除舊文件。

用到的軟件和技術有：xtrabackup（免費的mysql備份程序），qpress（xtrabackup壓縮需要的依賴，據說壓縮比很高），python3.5（ssh的遠程抓取，因為我不會bash）。

mkdir -p /root/42/script
cd /root/42/script
#安裝qpress
wget http://www.quicklz.com/qpress-11-linux-x64.tar
tar xf qpress-11-linux-x64.tar
mv qpress /usr/local/bin/
#centos6安裝xtrabackup
yum install http://www.percona.com/downloads/percona-release/redhat/0.1-4/percona-release-0.1-4.noarch.rpm
yum install libev -y
yum install percona-xtrabackup-24 -y
#新建backup.sh（來源未知）內容如下：

#!/bin/bash

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin
 
BACKUP_BASE_DIR="/data/backup/xtrabackup"
INC_BASE_LIST="${BACKUP_BASE_DIR}/inc_list.txt"
XTRABACKUP_PATH="/usr/bin/innobackupex"
 
MYSQL_CNF="/etc/my.cnf"
MYSQL_HOSTNAME=127.0.0.1
MYSQL_USERNAME=root
MYSQL_PASSWORD=""
 
LOCK_FILE="/tmp/innobackupex.lock"
THREAD=3
 
mkdir -p ${BACKUP_BASE_DIR}
CURRENT_BACKUP_PATH="${BACKUP_BASE_DIR}/$(date +%F_%H-%M)"
[[ -d ${CURRENT_BACKUP_PATH} ]] && CURRENT_BACKUP_PATH="${BACKUP_BASE_DIR}/$(date +%F_%H-%M-%S)"
 
print_help(){
    echo "--------------------------------------------------------------"
    echo "Usage: $0 full | inc | help               "
    echo "--------------------------------------------------------------"
    exit 1
}
 
[[ $# -lt 1 || "$1" == "help" ]] && print_help
 
[[ -f "$LOCK_FILE" ]] && echo -e "Usage: rm -f $LOCK_FILE\nUsage: chattr -i $LOCK_FILE && rm -f $LOCK_FILE" && exit 1
 
FullBackup(){
    touch $LOCK_FILE
    chattr +i $LOCK_FILE
    local rc=0
    ${XTRABACKUP_PATH} \
    --defaults-file=${MYSQL_CNF} \
    --user=${MYSQL_USERNAME} \
    --password=${MYSQL_PASSWORD} \
    --host=${MYSQL_HOSTNAME} \
    --compress \
    --compress-threads=${THREAD} \
    --parallel=${THREAD} \
    --no-timestamp ${CURRENT_BACKUP_PATH} > ${CURRENT_BACKUP_PATH}_full.log 2>&1
    grep ".*\ completed\ OK\!" ${CURRENT_BACKUP_PATH}_full.log > /dev/null 2>&1
    if [ $? -ne 0 ];then
        rc=1
        [[ -d ${CURRENT_BACKUP_PATH} && $(pwd) != "/" ]] && rm -rf ${CURRENT_BACKUP_PATH}
    else
        echo "NULL|${CURRENT_BACKUP_PATH}|full" >> ${INC_BASE_LIST}
        [[ -d ${CURRENT_BACKUP_PATH} && $(pwd) != "/" ]] && chattr +i ${CURRENT_BACKUP_PATH} || rc=1
    fi
    chattr -i ${LOCK_FILE}
    rm -f $LOCK_FILE
    chattr +a ${INC_BASE_LIST}
    return $rc
}
 
IncBackup(){
    touch $LOCK_FILE
    chattr +i $LOCK_FILE
    local rc=0
    PREV_BACKUP_DIR=$(sed '/^$/d' ${INC_BASE_LIST} | tail -1 | awk -F '|' '{print $2}')
    ${XTRABACKUP_PATH} \
    --defaults-file=${MYSQL_CNF} \
    --user=${MYSQL_USERNAME} \
    --password=${MYSQL_PASSWORD} \
    --host=${MYSQL_HOSTNAME} \
    --compress \
    --compress-threads=${THREAD} \
    --no-timestamp --incremental ${CURRENT_BACKUP_PATH} \
    --incremental-basedir=${PREV_BACKUP_DIR} > ${CURRENT_BACKUP_PATH}_inc.log 2>&1
    grep ".*\ completed\ OK\!" ${CURRENT_BACKUP_PATH}_inc.log > /dev/null 2>&1
    if [ $? -ne 0 ];then
        rc=1
        [[ -d ${CURRENT_BACKUP_PATH} && $(pwd) != "/" ]] && rm -rf ${CURRENT_BACKUP_PATH}
    else
        echo "${PREV_BACKUP_DIR}|${CURRENT_BACKUP_PATH}|inc" >> ${INC_BASE_LIST}
        [[ -d ${CURRENT_BACKUP_PATH} && $(pwd) != "/" ]] && chattr +i ${CURRENT_BACKUP_PATH} || rc=1
    fi
    chattr -i ${LOCK_FILE}
    rm -f $LOCK_FILE
    chattr +a ${INC_BASE_LIST}
    return $rc
}
 
## 全量備份
if [ "$1" == "full" ];then
    FullBackup
fi
 
## 增量備份
if [ "$1" == "inc" ];then
    ## 若全量備份不存在，則執行全量備份
    if [[ ! -f ${INC_BASE_LIST} || $(sed '/^$/d' ${INC_BASE_LIST} | wc -l) -eq 0 ]];then
        FullBackup
    else
        IncBackup
    fi
fi
 
## 刪除22天前的備份
if [[ -d ${BACKUP_BASE_DIR} && $(pwd) != "/" ]];then
    find ${BACKUP_BASE_DIR} -name "$(date -d '22 days ago' +'%F')_*" | xargs chattr -i
    find ${BACKUP_BASE_DIR} -name "$(date -d '22 days ago' +'%F')_*" | xargs rm -rf
fi

#可能需要修改backup.sh中的如下參數
BACKUP_BASE_DIR="/data/backup/xtrabackup"
XTRABACKUP_PATH="/usr/bin/innobackupex"
 
MYSQL_CNF="/etc/my.cnf"
MYSQL_HOSTNAME=127.0.0.1
MYSQL_USERNAME=root
MYSQL_PASSWORD=""
#給腳本添加執行權限
chmod 755 /root/42/script/backup.sh
#执行一次全量备份
/root/42/script/backup.sh full
#如果沒有錯誤信息，就可以看到BACKUP_BASE_DIR下生成了備份文件
#檢查下cron是否啟動
service crond status
#如果未啟動則將cron設置為開機啟動並手動啟動下
chkconfig crond on
service crond start
#添加定時任務
crontab -e
#在底部新增內容
## 每周六凌晨3:30一次全量备份
## 每周二、四、日的凌晨3:30点执行增量备份
30 3 * * 6 /root/42/script/backup.sh full
30 3 * * 2,4,7 /root/42/script/backup.sh inc

本文更新於 2017/09/25。