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- Percona XtraBackup特性说明
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- Percona Xtrabackup 备份恢复权限限制
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- 创建备份用户、配置参数及数据准备
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- 全量备份与恢复
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- 增量备份
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- 压缩备份
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- 流备份
1. Percona XtraBackup 特性说明
1)Percona Xtrabackup 8.0.26新增支持MyRocks存储引擎，不支持TokuDB引擎
2)Percona Xtrabackup 8.0.26 不支持低于MySQL 8.0的备份（因为MySQL 8.0在数据字典、redo log中和之前版本不兼容）
3)Percona Xtrabackup 8.0.26 目前X86版本可以从官方下载，ARM版本需要手动编译
4)备份文件必须是空的，没有任何文件
2. Percona Xtrabackup 备份恢复权限限制
1)备份路径需要有可读写权限
2)reload和Lock Tables（指定–no-locak选项除外），因为备份前需要执行FLUSH TABLES WITH READ LOCK和FLUSH ENGINE LOGS
3)Backup_admin权限,因为备份时需要查询performance_schema.log_status表并运行LOCK INSTANCE FOR BACKUP, LOCK BINLOG FOR BACKUP, or LOCK TABLES FOR BACKUP
4)Replication client权限。备份时为了读取二进制日志文件
5)Create tablespace权限。恢复表时需要创建表
6)Process权限。备份时需要运行show engine innodb status命令
7)Super权限。为了在复制环境中启动/停止复制线程
8)Create权限。为了创建percona_schema.xtrbackup_history表
9)Alter权限。为了更新percona_schema.xtrbackup_history表
10)Insert权限。为了将历史记录插入到percona_schema.xtrbackup_history表
11)Select权限。为了查询历史数据
3. 创建备份用户、配置参数及数据准备
//创建用户
mysql > CREATE USER 'bkpuser' @ 'localhost' IDENTIFIED BY 's3cr%T' ;
mysql > GRANT BACKUP_ADMIN,PROCESS,RELOAD,LOCK TABLES,REPLICATION CLIENT ON *.* TO 'bkpuser' @ 'localhost' ;
mysql > GRANT SELECT ON performance_schema.log_status TO 'bkpuser' @ 'localhost' ;
Mysql > GRANT SELECT ON performance_schema.keyring_component_status TO bkpuser @ 'localhost'
mysql > FLUSH PRIVILEGES ;
配置参数，Xtrbackup在备份时会读取MySQL的my.cnf配置文件中[mysqld]和[xtrabackup]部分，所以我们可以在配置文件中设置备份的目录[xtrabackup],target_dir = /data/backups/mysql
注意：如果my.cnf配置文件中有–set-variable==，xtrabackup不识别，需要使用–veriable=value代替 版本检测,Percona xtrabackup 8.0.21添加了–no-server-version-check参数，会将备份源版本和Percona Xtrabackup版本对比
源系统和PXB版本一样，备份继续 源系统低于PXB版本，备份继续 源系统大于PXB版本，且参数未被覆盖，停止备份并返回错误 源系统大于PXB版本，参数被覆盖，备份继续
Shell> xtrabackup --backup --no-server-version-check --target-dir = $mysql /backup1
覆盖参数时，可能会发生备份失败、创建损坏的备份、备份成功
3.1 Sysbench造数据
mysql> create database sbtest;
//使用sysbench造数
Shell> sysbench /usr/share/sysbench/oltp_read_write.lua --mysql-host=172.16.50.161 --mysql-port=3306 --mysql-user='root' --mysql-password='123456' --mysql-db='sbtest' --tables=1 --table-size=5000 --threads=20 prepare
//检查
MySQL [sbtest]> select count(*) from sbtest.sbtest1;
+----------+
| count(*) |
+----------+
| 5000 |
+----------+
1 row in set (0.00 sec)
4. 全量备份与恢复
4.1 全量备份
Shell> xtrabackup --defaults-file=/data1/mysqldata/my.cnf --socket=/data1/mysqldata/data/mysql.sock --user=root --password=123456 --port=3306 --backup --target-dir=/data1/xtrabackup/full/
输出信息：
210913 14:07:01 Finished backing up non-InnoDB tables and files
210913 14:07:01 Executing FLUSH NO_WRITE_TO_BINLOG BINARY LOGS
210913 14:07:01 Selecting LSN and binary log position from p_s.log_status
210913 14:07:01 [00] Copying /data1/mysqldata/log/binlog.000004 to /data1/xtrabackup/full/binlog.000004 up to position 196
210913 14:07:01 [00]...done
210913 14:07:01 [00] Writing /data1/xtrabackup/full/binlog.index
210913 14:07:01 [00]...done
210913 14:07:01 [00] Writing /data1/xtrabackup/full/xtrabackup_binlog_info
210913 14:07:01 [00]...done
210913 14:07:01 Executing FLUSH NO_WRITE_TO_BINLOG ENGINE LOGS...
xtrabackup: The latest check point (for incremental): '19442549'
xtrabackup: Stopping log copying thread at LSN 19442549.
Starting to parse redo log at lsn = 19442226
210913 14:07:01 Executing UNLOCK INSTANCE
210913 14:07:01 All tables unlocked
210913 14:07:01 [00] Copying ib_buffer_pool to /data1/xtrabackup/full/ib_buffer_pool
210913 14:07:01 [00]...done
210913 14:07:01 Backup created in directory '/data1/xtrabackup/full/'
MySQL binlog position: filename 'binlog.000004', position '196', GTID of the last change '8950f324-1441-11ec-b9b5-080027193a00:1-15'
210913 14:07:01 [00] Writing /data1/xtrabackup/full/backup-my.cnf
210913 14:07:01 [00]...done
210913 14:07:01 [00] Writing /data1/xtrabackup/full/xtrabackup_info
210913 14:07:01 [00]...done
xtrabackup: Transaction log of lsn (19442549) to (19442559) was copied.
210913 14:07:02 completed OK!
4.2 全量恢复
准备工作,由于使用–backup备份数据文件时时间点时不一致的（备份增量redo日志线程会实时监听增量数据），因为程序在不同的时间点复制，并且再复制过程中可能会被更改，如果使用innodb直接尝试启动这些数据文件，innodb将检测损坏并停止运行，所以需要使用–prepare将将备份文件进行崩溃恢复，来使用这些复制文件
Shell>xtrabackup --prepare --target-dir=/data1/xtrabackup/full
// 拷贝数据 注意：需要将源目录进行备份，且恢复目录要为空
Shell> xtrabackup --copy-back --target-dir=/data1/xtrabackup/full
// 修改目录属性启动数据库
Shell> chown -R mysql:mysql /data/mysqldata/data
Shell> chmod -R 755 /data/mysqldata/data
// 启动数据库
Shell> /data1/mysql/bin/mysqld --defaults-file=/data1/mysqldata/my.cnf --user=mysql &
// 检测
MySQL> select count(*) from sbtest.sbtest1;
5. 增量备份
增量备份需要在全量备份的基础上进行，每个innodb页面都包含一个日志序列号LSN。该LSN是整个数据库系统的版本号。每个页面的LSN显示最近更改的时间。增量备份时会将上一次全量备份的LSN或上一次增量备份的LSN和当前页面的LSN进行对比，通过两种算法继续查找。
第一种就是读取所有的数据页面直接检查页面LSN（适用所有版本MySQL），第二种就是在服务器上启用”更改页面跟踪“功能，该功能会在页面更改时进行记录，将信息保存下来，xtrbackup做增量备份时回去读取该信息，从而节省资源（该查找方法适用于percona server for MySQL）
- 全量备份
Shell> xtrabackup --defaults-file=/data1/mysqldata/my.cnf --socket=/data1/mysqldata/data/mysql.sock --user=root --password=123456 --port=3306 --backup --target-dir=/data1/xtrabackup/full/
- 应用中继日志
Shell> xtrabackup --prepare --apply-log-only --target-dir=/data1/xtrabackup/full
- 输出：
InnoDB: Shutdown completed; log sequence number 1626007
161011 12:41:04 completed OK!
- 增量备份:查看全量备份目录的xtrbackup_checkpoints
Shell> cat xtrabackup_checkpoints
backup_type = full-prepared //备份类型
from_lsn = 0 //开始LSN
to_lsn = 22254648//备份结束时LSN
last_lsn = 22254648 //上一个LSN号
flushed_lsn = 22254648//当前flush的LSN号
- 增量备份命令
Shell> xtrabackup --defaults-file=/data1/mysqldata/my.cnf --socket=/data1/mysqldata/data/mysql.sock --user=root --password=123456 --port=3306 --backup --target-dir=/data1/xtrabackup/inc1 --incremental-basedir=/data1/xtrabackup/full
- 输出信息：
210913 14:18:07 Finished backing up non-InnoDB tables and files
210913 14:18:07 Executing FLUSH NO_WRITE_TO_BINLOG BINARY LOGS
210913 14:18:07 Selecting LSN and binary log position from p_s.log_status
210913 14:18:07 [00] Copying /data1/mysqldata/log/binlog.000005 to /data1/xtrabackup/inc1/binlog.000005 up to position 196
210913 14:18:07 [00]...done
210913 14:18:07 [00] Writing /data1/xtrabackup/inc1/binlog.index
210913 14:18:07 [00]...done
210913 14:18:07 [00] Writing /data1/xtrabackup/inc1/xtrabackup_binlog_info
210913 14:18:07 [00]...done
210913 14:18:07 Executing FLUSH NO_WRITE_TO_BINLOG ENGINE LOGS...
xtrabackup: The latest check point (for incremental): '20799610'
xtrabackup: Stopping log copying thread at LSN 20804588.
Starting to parse redo log at lsn = 20799534
210913 14:18:07 >> log scanned up to (20804598)
210913 14:18:08 Executing UNLOCK INSTANCE
210913 14:18:08 All tables unlocked
210913 14:18:08 [00] Copying ib_buffer_pool to /data1/xtrabackup/inc1/ib_buffer_pool
210913 14:18:08 [00]...done
210913 14:18:08 Backup created in directory '/data1/xtrabackup/inc1/'
MySQL binlog position: filename 'binlog.000005', position '196', GTID of the last change '8950f324-1441-11ec-b9b5-080027193a00:1-20'
210913 14:18:08 [00] Writing /data1/xtrabackup/inc1/backup-my.cnf
210913 14:18:08 [00]...done
210913 14:18:08 [00] Writing /data1/xtrabackup/inc1/xtrabackup_info
210913 14:18:08 [00]...done
xtrabackup: Transaction log of lsn (20799610) to (20804624) was copied.
210913 14:18:09 completed OK!
//检查当前checkpoints点
Shell> cat xtrabackup_checkpoints
backup_type = incremental
from_lsn = 22254648
to_lsn = 33288485
last_lsn = 33299549
flushed_lsn = 33288485
From_lsn是备份的起始LSN，对于增量，他必须与前一个备份检查点to_lsn相同
- 应用中继日志
–prepare增量备份恢复时与全量备份不同，在全量备份时执行–prepare为了保证数据库一致，针对数据文件从日志文件重放已提交的事务，以及回滚未提交的事务。在增量时，必须跳过未提交事务的回滚，因为备份时未提交的事务可能正在进行中，很可能在下一次增量备份中提交，所以需要使用–apply-log-only选项来防止回滚阶段。
将第一个增量备份应用到全量备份中（增量文件将会应用到/data1/xtrbackup/full中）
Shell> xtrabackup --prepare --apply-log-only --target-dir=/data1/xtrabackup/full --incremental-dir=/data1/xtrabackup/inc1
输出信息：
incremental backup from 1626007 is enabled.
xtrabackup: cd to /data/backups/base
xtrabackup: This target seems to be already prepared with --apply-log-only.
xtrabackup: xtrabackup_logfile detected: size=2097152, start_lsn=(4124244)
...
xtrabackup: page size for /tmp/backups/inc1/ibdata1.delta is 16384 bytes
Applying /tmp/backups/inc1/ibdata1.delta to ./ibdata1...
...
161011 12:45:56 completed OK!
注意：全量备份中的to_LSN号和增量备份中的checkpoints的to_lsn号相同 如果做多次增量备份时，需要在每次做完增量备份后使用–prepare --apply-log-only将增量部分合并到全量备份中，否则会报lsn冲突
xtrabackup: This target seems to be already prepared with --apply-log-only.
xtrabackup: error: This incremental backup seems not to be proper for the target.
xtrabackup: Check 'to_lsn' of the target and 'from_lsn' of the incremental.
5.1 增量恢复
Shell> xtrabackup --prepare --target-dir=/data1/xtrabackup/full
// 拷回数据：
Shell> xtrabackup --defaults-file=/data1/mysqldata/my.cnf --copy-back --target-dir=/data1/xtrabackup/full
// 修改数据目录的权限和属性：
Shell> chown -R mysql:mysql /data1/mysqldata1
Shell> chmod -R 755 /data1/mysqldata1 启动数据库
Shell>/data1/mysql/bin/mysqld --defaults-file=/data1/mysqldata/my.cnf --user=mysql &
// 检测
MySQL> select count(*) from sbtest.sbtest1;
全备+增备恢复完成
6. 压缩备份
我们在备份时可以对备份文件进行压缩备份，使用–compress选项
Shell> xtrabackup --defaults-file=/data1/mysqldata/my.cnf --socket=/data1/mysqldata/data/mysql.sock --user=root --password=123456 --port=3306 --backup --compress --target-dir=/data1/xtrabackup/full
由于–compress使用到了qpress，所以需要安装percona-release包
Shell> suudo percona-release enable tools
Shell> sudo apt-get update
Shell> sudo apt-get install qpress
增加备份线程
Shell> xtrabackup --defaults-file=/data1/mysqldata/my.cnf --socket=/data1/mysqldata/data/mysql.sock --user=root --password=123456 --port=3306 --backup --compress --compress-threads=4 --target-dir=/data1/xtrabackup/full
输出如下信息：
...
170223 13:00:38 [01] Compressing ./test/sbtest1.frm to /tmp/compressed/test/sbtest1.frm.qp
170223 13:00:38 [01]...done
170223 13:00:38 [01] Compressing ./test/sbtest2.frm to /tmp/compressed/test/sbtest2.frm.qp
170223 13:00:38 [01]...done
...
170223 13:00:39 [00] Compressing xtrabackup_info
170223 13:00:39 [00]...done
xtrabackup: Transaction log of lsn (9291934) to (9291934) was copied.
170223 13:00:39 completed OK!
6.1 解压备份及恢复
解压文件：
Shell> xtrabackup --decompress --target-dir=/data/compressed/
Shell> xtrabackup --prepare --target-dir=/data/compressed/
InnoDB: Starting shutdown...
InnoDB: Shutdown completed; log sequence number 9293846
170223 13:39:31 completed OK!
备份恢复：
Shell> xtrabackup --copy-back --target-dir=/data/backups/
7. 流备份
使用流备份传输到名为 backup.xbstream
Shell> xtrabackup --backup --stream=xbstream --target-dir=./ > backup.xbstream
加密备份
Shell> xtrabackup –backup –stream=xbstream ./ > backup.xbstream gzip - | openssl des3 -salt -k “密码” > backup.xbstream.gz.des3
加压备份到当前目录
Shell> xbstream -x < backup.xbstream
使用流备份方式到其他服务器上
Shell> xtrbackup --backup --stream=xbstream --target-dir=./ | ssh user@otherhost "xbstream -x "
限制备份工具的吞吐量为10MB/秒
Shell> xtrabackup –backup –stream=xbstream ./ | pv -q -L10m ssh user@desthost “cat - > /data/backups/backup.xbstream”
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