基於邏輯卷LVM的MySQL、mariadb數據庫備份還原詳細實現
阿新 • • 發佈：2018-03-18
快照恢復數據庫 lvm 前提是數據庫的數據是放在邏輯卷上的；
數據庫數據和日誌分開存放；正常情況下數據和日誌是放在兩個獨立的磁盤上，如果是raid的話，那麽就無所謂了。
創建分區：
[root@mysql ~]$fdisk /dev/sda
Command (m for help): n
All primary partitions are in use
Adding logical partition 6
First sector (153098240-419430399, default 153098240):
Using default value 153098240
Last sector, +sectors or +size{K,M,G} (153098240-419430399, default 419430399): +10G
Partition 6 of type Linux and of size 10 GiB is set
Command (m for help): t
Partition number (1-6, default 6): 6
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
[root@mysql ~]$partprobe
Warning: Unable to open /dev/sr0 read-write (Read-only file system). /dev/sr0 has been opened read-only.
[root@mysql ~]$lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 200G 0 disk
├─sda1 8:1 0 1G 0 part /boot
├─sda2 8:2 0 50G 0 part /
├─sda3 8:3 0 20G 0 part /app
├─sda4 8:4 0 512B 0 part
├─sda5 8:5 0 2G 0 part [SWAP]
└─sda6 8:6 0 10G 0 part
sr0 11:0 1 8.1G 0 rom
loop0 7:0 0 8.1G 1 loop /mnt/cdrom創建PV，vg，lv：
加入PV、VG和LV；
[root@mysql ~]$pvcreate /dev/sda6
Physical volume "/dev/sda6" successfully created.
[root@mysql ~]$pvs
PV VG Fmt Attr PSize PFree
/dev/sda6 lvm2 --- 10.00g 10.00g
[root@mysql ~]$vgcreate vg0 /dev/sda6
Volume group "vg0" successfully created
[root@mysql ~]$vgs
VG #PV #LV #SN Attr VSize VFree
vg0 1 0 0 wz--n- <10.00g <10.00g
[root@mysql ~]$vgdisplay
--- Volume group ---
VG Name vg0
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size <10.00 GiB
PE Size 4.00 MiB
Total PE 2559
Alloc PE / Size 0 / 0
Free PE / Size 2559 / <10.00 GiB
VG UUID fuGxOy-IVrf-SnWd-C0ie-eb9O-LIWz-sMx17T
[root@mysql ~]$pvs
PV VG Fmt Attr PSize PFree
/dev/sda6 vg0 lvm2 a-- <10.00g <10.00g
創建的LV，剩余的空間用於放置快照數據；
[root@mysql ~]$lvcreate -n mysqldata -L 2G vg0
Logical volume "mysqldata" created.
[root@mysql ~]$lvcreate -n binlogs -L 3G vg0
Logical volume "binlogs" created.
[root@mysql ~]$pvs
PV VG Fmt Attr PSize PFree
/dev/sda6 vg0 lvm2 a-- <10.00g <5.00g
[root@mysql ~]$vgs
VG #PV #LV #SN Attr VSize VFree
vg0 1 2 0 wz--n- <10.00g <5.00g
格式化文件系統：
[root@mysql ~]$mkfs.xfs /dev/vg0/mysqldata
meta-data=/dev/vg0/mysqldata isize=512 agcount=4, agsize=131072 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=524288, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@mysql ~]$mkfs.xfs /dev/vg0/binlogs
meta-data=/dev/vg0/binlogs isize=512 agcount=4, agsize=196608 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=786432, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@mysql ~]$
[root@mysql ~]$blkid
/dev/sda1: UUID="07deeea1-2041-4e34-98ba-2529dfb30c32" TYPE="xfs"
/dev/sda2: UUID="a7595dc1-7958-4728-954b-e8dcfb6bca3c" TYPE="xfs"
/dev/sda3: UUID="3c26d76c-a6a6-4c40-90fd-c2a38520b674" TYPE="xfs"
/dev/sda5: UUID="7f480b58-5216-4561-a933-43766aa0ff05" TYPE="swap"
/dev/sda6: UUID="1dGdT7-kPEX-pLCH-id8y-0269-244Y-3hiJcW" TYPE="LVM2_member"
/dev/sr0: UUID="2017-09-06-10-53-42-00" LABEL="CentOS 7 x86_64" TYPE="iso9660" PTTYPE="dos"
/dev/loop0: UUID="2017-09-06-10-53-42-00" LABEL="CentOS 7 x86_64" TYPE="iso9660" PTTYPE="dos"
/dev/mapper/vg0-mysqldata: UUID="6f9f0f27-dba5-4479-adb6-532362d80d38" TYPE="xfs"
/dev/mapper/vg0-binlogs: UUID="150de97a-7a76-465e-9d6a-1357600fa152" TYPE="xfs"提供數據目錄，掛載：
[root@mysql ~]$mkdir /data/{mysqldata,binlogs} -pv
mkdir: created directory ‘/data’
mkdir: created directory ‘/data/mysqldata’
mkdir: created directory ‘/data/binlogs’
[root@mysql ~]$ll /data/
total 0
drwxr-xr-x 2 root root 6 Feb 25 10:07 binlogs
drwxr-xr-x 2 root root 6 Feb 25 10:07 mysqldata
[root@mysql ~]$vim /etc/fstab
...
UUID=6f9f0f27-dba5-4479-adb6-532362d80d38 /data/mysqldata/ xfs defaults 0 0
UUID=150de97a-7a76-465e-9d6a-1357600fa152 /data/binlogs/ xfs defaults 0 0
[root@mysql ~]$mount -a
[root@mysql ~]$df -Ph
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 50G 3.5G 47G 7% /
devtmpfs 474M 0 474M 0% /dev
tmpfs 489M 0 489M 0% /dev/shm
tmpfs 489M 7.2M 482M 2% /run
tmpfs 489M 0 489M 0% /sys/fs/cgroup
/dev/sda3 20G 33M 20G 1% /app
/dev/loop0 8.1G 8.1G 0 100% /mnt/cdrom
/dev/sda1 1014M 158M 857M 16% /boot
tmpfs 98M 0 98M 0% /run/user/0
/dev/mapper/vg0-mysqldata 2.0G 33M 2.0G 2% /data/mysqldata
/dev/mapper/vg0-binlogs 3.0G 33M 3.0G 2% /data/binlogs
[root@mysql ~]$ll /data/
total 0
drwxr-xr-x 2 root root 6 Feb 25 10:05 binlogs
drwxr-xr-x 2 root root 6 Feb 25 10:05 mysqldata
[root@mysql ~]$chown -R mysql.mysql /data/
[root@mysql ~]$ll /data/
total 0
drwxr-xr-x 2 mysql mysql 6 Feb 25 10:07 binlogs
drwxr-xr-x 2 mysql mysql 6 Feb 25 10:07 mysqldata
[root@mysql ~]$ll /data/ -d
drwxr-xr-x 4 mysql mysql 38 Feb 25 10:07 /data/提供數據：
vim /etc/my.cnf [mysqld] #datadir=/var/lib/mysql datadir=/data/mysqldata/ socket=/var/lib/mysql/mysql.sock # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 log_bin=/data/binlogs/mysql-bin innodb_file_per_table [root@mysql ~]$ll /data/ -d drwxr-xr-x 4 mysql mysql 38 Feb 25 10:07 /data/ [root@mysql ~]$ll /data/ total 0 drwxr-xr-x 2 mysql mysql 101 Feb 25 10:17 binlogs drwxr-xr-x 5 mysql mysql 159 Feb 25 10:17 mysqldata [root@mysql ~]$ll /data/mysqldata/ total 36892 -rw-rw---- 1 mysql mysql 16384 Feb 25 10:17 aria_log.00000001 -rw-rw---- 1 mysql mysql 52 Feb 25 10:17 aria_log_control -rw-rw---- 1 mysql mysql 18874368 Feb 25 10:17 ibdata1 -rw-rw---- 1 mysql mysql 5242880 Feb 25 10:17 ib_logfile0 -rw-rw---- 1 mysql mysql 5242880 Feb 25 10:17 ib_logfile1 drwx------ 2 mysql mysql 4096 Feb 25 10:17 mysql drwx------ 2 mysql mysql 4096 Feb 25 10:17 performance_schema drwx------ 2 mysql mysql 6 Feb 25 10:17 test [root@mysql ~]$ll /data/binlogs/ total 1056 -rw-rw---- 1 mysql mysql 30331 Feb 25 10:17 mysql-bin.000001 -rw-rw---- 1 mysql mysql 1038814 Feb 25 10:17 mysql-bin.000002 -rw-rw---- 1 mysql mysql 245 Feb 25 10:17 mysql-bin.000003 -rw-rw---- 1 mysql mysql 93 Feb 25 10:17 mysql-bin.index [root@mysql ~]$mysql < hellodb_InnoDB.sql MariaDB [(none)]> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | hellodb | | mysql | | performance_schema | | test | +--------------------+ 5 rows in set (0.00 sec) MariaDB [(none)]> show binary logs; +------------------+-----------+ | Log_name | File_size | +------------------+-----------+ | mysql-bin.000001 | 30331 | | mysql-bin.000002 | 1038814 | | mysql-bin.000003 | 7655 | +------------------+-----------+ 3 rows in set (0.00 sec) 開始備份之前，需要先加全局讀鎖； MariaDB [(none)]> flush tables with read lock; Query OK, 0 rows affected (0.00 sec)
刷新日誌，記錄二進制日誌的位置：
MariaDB [(none)]> flush logs; Query OK, 0 rows affected (0.01 sec) MariaDB [(none)]> show binary logs; +------------------+-----------+ | Log_name | File_size | +------------------+-----------+ | mysql-bin.000001 | 30331 | | mysql-bin.000002 | 1038814 | | mysql-bin.000003 | 7698 | | mysql-bin.000004 | 245 | +------------------+-----------+ 4 rows in set (0.00 sec) 記錄二進制日誌的位置： [root@mysql ~]$mysql -e 'show binary logs' +------------------+-----------+ | Log_name | File_size | +------------------+-----------+ | mysql-bin.000001 | 30331 | | mysql-bin.000002 | 1038814 | | mysql-bin.000003 | 7698 | | mysql-bin.000004 | 245 | +------------------+-----------+ [root@mysql ~]$mysql -e 'show binary logs' > pos.log
使用lv創建數據庫快照：
[root@mysql ~]$lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert binlogs vg0 -wi-ao---- 3.00g mysqldata vg0 -wi-ao---- 2.00g [root@mysql ~]$lvcreate -n mysqldata-snapshot -s -p r -L 2G /dev/vg0/mysqldata Using default stripesize 64.00 KiB. Logical volume "mysqldata-snapshot" created. [root@mysql ~]$lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert binlogs vg0 -wi-ao---- 3.00g mysqldata vg0 owi-aos--- 2.00g mysqldata-snapshot vg0 sri-a-s--- 2.00g mysqldata 0.00 [root@mysql ~]$lvdisplay --- Logical volume --- LV Path /dev/vg0/mysqldata-snapshot LV Name mysqldata-snapshot VG Name vg0 LV UUID oQZBaU-IEld-M2wc-IQHo-A8nH-e53J-SrRujn LV Write Access read only LV Creation host, time mysql, 2018-02-25 10:25:18 +0800 LV snapshot status active destination for mysqldata LV Status available # open 0 LV Size 2.00 GiB Current LE 512 COW-table size 2.00 GiB COW-table LE 512 Allocated to snapshot 0.00% Snapshot chunk size 4.00 KiB Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:4 當做完快照後，那麽就可以繼續讓用戶訪問數據庫了； MariaDB [(none)]> unlock tables; Query OK, 0 rows affected (0.00 sec) 修改和破壞操作； MariaDB [(none)]> delete from hellodb.students; Query OK, 25 rows affected (0.01 sec)
掛載快照，將數據備份出來；
直接掛載是掛載不了的，因為兩個設備文件的UUID是一樣的；
/dev/mapper/vg0-mysqldata: UUID="6f9f0f27-dba5-4479-adb6-532362d80d38" TYPE="xfs"
/dev/mapper/vg0-binlogs: UUID="150de97a-7a76-465e-9d6a-1357600fa152" TYPE="xfs"
/dev/mapper/vg0-mysqldata--snapshot: UUID="6f9f0f27-dba5-4479-adb6-532362d80d38" TYPE="xfs"
[root@mysql ~]$man mount
nouuid Don''t check for double mounted file systems using the file system uuid. This is useful to mount LVM snapshot vol‐
umes, and often used in combination with "norecovery" for mounting read-only snapshots.
[root@mysql ~]$mkdir /mnt/snap
[root@mysql ~]$mount -o nouuid,norecovery /dev/vg0/mysqldata-snapshot /mnt/snap/
mount: /dev/mapper/vg0-mysqldata--snapshot is write-protected, mounting read-only
[root@mysql ~]$df -Ph
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 50G 3.4G 47G 7% /
devtmpfs 474M 0 474M 0% /dev
tmpfs 489M 0 489M 0% /dev/shm
tmpfs 489M 7.2M 482M 2% /run
tmpfs 489M 0 489M 0% /sys/fs/cgroup
/dev/sda3 20G 33M 20G 1% /app
/dev/loop0 8.1G 8.1G 0 100% /mnt/cdrom
/dev/sda1 1014M 158M 857M 16% /boot
tmpfs 98M 0 98M 0% /run/user/0
/dev/mapper/vg0-mysqldata 2.0G 63M 2.0G 4% /data/mysqldata
/dev/mapper/vg0-binlogs 3.0G 34M 3.0G 2% /data/binlogs
/dev/mapper/vg0-mysqldata--snapshot 2.0G 31M 2.0G 2% /mnt/snap
建議打包，放在遠程存儲上；有些企業使用磁帶機進行備份；
[root@mysql ~]$mkdir /backups
[root@mysql ~]$cd /mnt/snap/
[root@mysql snap]$ls
aria_log.00000001 aria_log_control hellodb ibdata1 ib_logfile0 ib_logfile1 mysql performance_schema test
[root@mysql snap]$cp -a /mnt/snap/* /backups/
[root@mysql snap]$ll /backups/ -h
total 29M
-rw-rw---- 1 mysql mysql 16K Feb 25 10:17 aria_log.00000001
-rw-rw---- 1 mysql mysql 52 Feb 25 10:17 aria_log_control
drwx------ 2 mysql mysql 272 Feb 25 10:19 hellodb
-rw-rw---- 1 mysql mysql 18M Feb 25 10:19 ibdata1
-rw-rw---- 1 mysql mysql 5.0M Feb 25 10:19 ib_logfile0
-rw-rw---- 1 mysql mysql 5.0M Feb 25 10:17 ib_logfile1
drwx------ 2 mysql mysql 4.0K Feb 25 10:17 mysql
drwx------ 2 mysql mysql 4.0K Feb 25 10:17 performance_schema
drwx------ 2 mysql mysql 6 Feb 25 10:17 test
刪除快照，否則影響性能；
[root@mysql snap]$umount /mnt/snap/
umount: /mnt/snap: target is busy.
(In some cases useful info about processes that use
the device is found by lsof(8) or fuser(1))
[root@mysql snap]$cd
[root@mysql ~]$umount /mnt/snap/
[root@mysql ~]$lvremove /dev/vg0/mysqldata-snapshot
Do you really want to remove active logical volume vg0/mysqldata-snapshot? [y/n]: y
Logical volume "mysqldata-snapshot" successfully removed數據庫出現故障的模擬：
需要停止數據庫服務；
[root@mysql ~]$systemctl stop mariadb
[root@mysql ~]$rm -rf /data/mysqldata/*
數據庫的還原操作：
[root@mysql ~]$cp -a /backups/* /data/mysqldata/
[root@mysql ~]$systemctl start mariadb
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| hellodb |
| mysql |
| performance_schema |
| test |
+--------------------+
MariaDB [(none)]> show master logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000001 | 30331 |
| mysql-bin.000002 | 1038814 |
| mysql-bin.000003 | 7698 |
| mysql-bin.000004 | 442 |
| mysql-bin.000005 | 245 |
+------------------+-----------+
5 rows in set (0.00 sec)
此時只是恢復了一部分的數據，但是不是最新的，要想恢復至最新狀態，那麽需要使用
mysql-bin.000004 245和mysql-bin.000005 245之間的二進制完成恢復；
[root@mysql ~]$ls
all_2018-02-24_21:46:13.sql anaconda-ks.cfg hellodb_InnoDB.sql mariadb-bin.000010 r7.sh
all.sql binlog.sql initial-setup-ks.cfg pos.log
[root@mysql ~]$less pos.log
Log_name File_size
mysql-bin.000001 30331
mysql-bin.000002 1038814
mysql-bin.000003 7698
mysql-bin.000004 245
[root@mysql ~]$cd /data/binlogs/
[root@mysql binlogs]$ls
mysql-bin.000001 mysql-bin.000002 mysql-bin.000003 mysql-bin.000004 mysql-bin.000005 mysql-bin.index
[root@mysql binlogs]$cp -a mysql-bin.00000{4,5} ~
MariaDB [(none)]> flush tables with read lock;
Query OK, 0 rows affected (0.00 sec)
[root@mysql ~]$mysqlbinlog --start-position=245 mysql-bin.000004 > binlog.sql
[root@mysql ~]$mysqlbinlog mysql-bin.000005 >> binlog.sql
MariaDB [(none)]> set sql_log_bin=0;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> unlock tables;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> source binlog.sql
此時發現students表是空的；
MariaDB [(none)]> select * from hellodb.students;
註意：
MySQLdump 的備份是溫備；
他的效率也不是特別的高，因為他的備份是相當於對MySQL數據庫進行的查詢操作的結果；
如果是T級別的數據庫，那麽查詢備份就需要大量的時間。基於邏輯卷LVM的MySQL、mariadb數據庫備份還原詳細實現