使用innobackupex进行mysql备份

使用innobackupex备份MySQL数据库

安装innobackupex

安装yum扩展源：

[root@adailinux ~]# rpm -ivh  http://www.percona.com/downloads/percona-release/redhat/0.1-3/percona-release-0.1-3.noarch.rpm

安装innobackupex

[root@adailinux ~]# yum install -y percona-xtrabackup

进行全量备份

说明： 使用xtrabackup进行备份需要使用mysql用户，该用户需要有备份的权限。

创建mysql用户

创建mysql用户：
[root@adailinux ~]# mysql -uroot -p'123456'
Welcome to the MySQL monitor.
mysql> grant RELOAD, LOCK TABLES, REPLICATION CLIENT on *.* to 'bakuser'@'localhost' identified by '123456';
Query OK, 0 rows affected (0.13 sec)
#该用户只需要有备份权限即可，所以在创建用户时只授予其部分权限
mysql> flush privileges；
Query OK, 0 rows affected (0.05 sec)
#刷新！
mysql> quit
Bye

全量备份

创建一个目录用于存放备份文件：
[root@adailinux ~]# mkdir /data/backup

开始备份：
[root@adailinux ~]# innobackupex --defaults-file=/etc/my.cnf --user=bakuser --password='123456' -S /tmp/mysql.sock /data/backup
至此，备份完成！

说明：

--defaults-file：指定mysql的配置文件（该参数必须放在首位）

--user：指定用于备份的mysql用户

--password：mysql用户密码

-S：=socket，指定MySQL的socket文件（也可以使用-h，该参数非必须！）

查看备份文件：

[root@adailinux ~]# cd /data/backup/
[root@adailinux backup]# ls
2017-08-23_08-49-22
[root@adailinux backup]# ls 2017-08-23_08-49-22/
backup-my.cnf  mysql               test                    xtrabackup_info
ibdata1        performance_schema  xtrabackup_checkpoints  xtrabackup_logfile

注： ibdata1为核心文件，其中存放的是：储存格式；INNODB类型数据状态下，ibdata用来储存文件的数据，而库名的文件夹里面的那些表文件只是结构而已。

恢复数据库

在恢复数据库之前需要先停止MySQL服务！

终止mysql服务：
[root@adailinux backup]# /etc/init.d/mysqld stop
Shutting down MySQL.. SUCCESS!

恢复准备：

[root@adailinux backup]# mv /data/mysql /data/mysql.bak
[root@adailinux backup]# mkdir /data/mysql
[root@adailinux backup]# chown mysql:mysql /data/mysql
#进行备份前将原/data/mysql中文件清空
#在此只为学习，所以只对该文件进行更名，然后重建该目录并更改权限

开始恢复：

匹配数据文件：

[root@adailinux backup]# innobackupex --use-memory=256M --apply-log /data/backup/2017-08-23_08-49-22

说明： 进行数据库恢复时，先匹配用于恢复的数据文件。

--use-memory：指定执行数据库恢复操作时的运行内存（添加该选项的目的通过指定其运行内存来加快恢复速度，可不加该参数）。

--apply-log：指定要恢复的数据文件（来自备份文件）

恢复：

[root@adailinux backup]# innobackupex --defaults-file=/etc/my.cnf --copy-back /data/backup/2017-08-23_08-49-22/
至此，数据库恢复完成！

说明：

--copy-back：指定用于恢复的数据文件目录

增量备份

增量备份是在全量备份的基础上进行的。

注： 该过程根据man文档进行操作。

Incremental Backups with innobackupex
As  not  all  information  changes between each backup, the incremental backup
strategy uses this to reduce the storage needs and the duration  of  making  a
backup.

This  can  be  done  because  each InnoDB page has a log sequence number, LSN,
which acts as a version number of the entire database. Every time the database
is modified, this number gets incremented.

An incremental backup copies all pages since a specific LSN.

Once  the pages have been put together in their respective order, applying the
logs will recreate the process that affected the database, yielding  the  data
at the moment of the most recently created backup.

Creating an Incremental Backups with innobackupex
First,  you  need to make a full backup as the BASE for subsequent incremental
backups:

$ innobackupex /data/backups

This will create a timestamped directory in /data/backups. Assuming  that  the
backup   is  done  last  day  of  the  month,  BASEDIR  would  be  /data/back‐
ups/2013-03-31_23-01-18, for example.

NOTE:
You can use the innobackupex --no-timestamp option to override this  behav‐
ior and the backup will be created in the given directory.

If  you  check  at the xtrabackup-checkpoints file in BASE-DIR, you should see
something like:

backup_type = full-backuped
from_lsn = 0
to_lsn = 1626007
last_lsn = 1626007
compact = 0
recover_binlog_info = 1

To create an incremental backup the next day, use the --incremental option and
provide the BASEDIR:

$ innobackupex --incremental /data/backups --incremental-basedir=BASEDIR

and  another  timestamped  directory will be created in /data/backups, in this
example, /data/backups/2013-04-01_23-01-18 containing the incremental  backup.
We will call this INCREMENTAL-DIR-1.

If  you  check  at  the  xtrabackup-checkpoints file in INCREMENTAL-DIR-1, you
should see something like:

backup_type = incremental
from_lsn = 1626007
to_lsn = 4124244
last_lsn = 4124244
compact = 0
recover_binlog_info = 1

Creating another incremental backup the next day will be analogous,  but  this
time the previous incremental one will be base:

$ innobackupex --incremental /data/backups --incremental-basedir=INCREMENTAL-DIR-1

Yielding  (in  this  example)  /data/backups/2013-04-02_23-01-18.  We will use
INCREMENTAL-DIR-2 instead for simplicity.

At this point, the xtrabackup-checkpoints  file  in  INCREMENTAL-DIR-2  should
contain something like:

backup_type = incremental
from_lsn = 4124244
to_lsn = 6938371
last_lsn = 7110572
compact = 0
recover_binlog_info = 1

As  it  was  said  before,  an  incremental  backup only copy pages with a LSN
greater than a specific value. Providing the LSN would have produced  directo‐
ries with the same data inside:

innobackupex --incremental /data/backups --incremental-lsn=4124244
innobackupex --incremental /data/backups --incremental-lsn=6938371

This is a very useful way of doing an incremental backup, since not always the
base or the last incremental will be available in the system.

WARNING:
This procedure only affects XtraDB or  InnoDB-based  tables.  Other  tables
with  a different storage engine, e.g. MyISAM, will be copied entirely each
time an incremental backup is performed.

Preparing an Incremental Backup with innobackupex
Preparing incremental backups is a bit different than full ones. This is, per‐
haps, the stage where more attention is needed:

• First,  only  the committed transactions must be replayed on each backup.
This will merge the base full backup with the incremental ones.

• Then, the uncommitted transaction must be rolled back in order to have  a
ready-to-use backup.

If  you replay the committed transactions and rollback the uncommitted ones on
the base backup, you will not be able to add the incremental ones. If  you  do
this on an incremental one, you won’t be able to add data from that moment and
the remaining increments.

Having this  in  mind,  the  procedure  is  very  straight-forward  using  the
--redo-only option, starting with the base backup:

innobackupex --apply-log --redo-only BASE-DIR

You should see an output similar to:

160103 22:00:12 InnoDB: Shutdown completed; log sequence number 4124244
160103 22:00:12 innobackupex: completed OK!

Then, the first incremental backup can be applied to the base backup, by issu‐
ing:

innobackupex --apply-log --redo-only BASE-DIR --incremental-dir=INCREMENTAL-DIR-1

You should see an output similar to the previous one  but  with  corresponding
LSN:

160103 22:08:43 InnoDB: Shutdown completed; log sequence number 6938371
160103 22:08:43 innobackupex: completed OK!

If  no  --incremental-dir is set, innobackupex will use the most recent subdi‐
rectory created in the basedir.

At this moment, BASE-DIR contains the data up  to  the  moment  of  the  first
incremental backup. Note that the full data will always be in the directory of
the base backup, as we are appending the increments to it.

Repeat the procedure with the second one:

innobackupex --apply-log BASE-DIR --incremental-dir=INCREMENTAL-DIR-2

If the “completed OK!” message was shown, the final data will be in  the  base
backup directory, BASE-DIR.

NOTE:
--redo-only  should  be  used when merging all incrementals except the last
one. That’s why the previous line doesn’t contain the  --redo-only  option.
Even  if  the  --redo-only was used on the last step, backup would still be
consistent but in that case server would perform the rollback phase.

You can use this procedure to add more increments to the base, as long as  you
do  it in the chronological order that the backups were done. If you merge the
incrementals in the wrong order, the backup  will  be  useless.  If  you  have
doubts about the order that they must be applied, you can check the file xtra‐
backup_checkpoints at the directory of each one, as shown in the beginning  of
this section.

Once  you  merge  the base with all the increments, you can prepare it to roll
back the uncommitted transactions:

innobackupex --apply-log BASE-DIR

Now your backup is ready to be  used  immediately  after  restoring  it.  This
preparation  step  is optional. However, if you restore without doing the pre‐
pare, the database server will begin to rollback uncommitted transactions, the
same  work  it  would do if a crash had occurred. This results in delay as the
database server starts, and you can avoid the delay if you do the prepare.

Note that the iblog* files will not be created by innobackupex,  if  you  want
them  to  be created, use xtrabackup –prepare on the directory. Otherwise, the
files will be created by the server once started.
Restoring Incremental Backups with innobackupex
After preparing the incremental backups, the base directory contains the  same
as a full one. For restoring it you can use:

innobackupex --copy-back BASE-DIR

and   you   may   have   to  change  the  ownership  as  detailed  on  restor‐
ing_a_backup_ibk.

创建增量备份

备份1：

[root@adailinux mysql]# innobackupex --defaults-file=/etc/my.cnf --user=bakuser --password='123456' --incremental /data/backup --incremental-basedir=/data/backup/2017-08-23_08-49-22

[root@adailinux backup]# ll
总用量 0
drwx------ 7 root root 235 8月  23 22:13 2017-08-23_08-49-22
drwx------ 6 root root 210 8月  23 22:12 2017-08-23_21-56-12

备份2：

[root@adailinux backup]# innobackupex --defaults-file=/etc/my.cnf --user=bakuser --password='123456' --incremental /data/backup --incremental-basedir=/data/backup/2017-08-23_21-56-12

[root@adailinux backup]# ll
总用量 0
drwx------ 7 root root 235 8月  23 22:13 2017-08-23_08-49-22
drwx------ 6 root root 210 8月  23 22:12 2017-08-23_21-56-12
drwx------ 7 root root 223 8月  23 22:13 2017-08-23_22-02-36

合并备份文件

[root@adailinux backup]# innobackupex --apply-log --redo-only /data/backup/2017-08-23_08-49-22

[root@adailinux backup]# innobackupex --apply-log --redo-only /data/backup/2017-08-23_08-49-22 --incremental-dir=/data/backup/2017-08-23_21-56-12

[root@adailinux backup]# innobackupex --apply-log  /data/backup/2017-08-23_08-49-22 --incremental-dir=/data/backup/2017-08-23_22-02-36

注意： 关于--redo-only参数，在进行增量备份文件的合并时，除了 在进行最后一份增量文件的合并时不需要添加该参数 外，其余都要加上该参数！！！

恢复

[root@adailinux backup]# innobackupex --copy-back /data/backup/2017-08-23_08-49-22