CentOS文件备份|还原

时间:2014-03-18 00:27
来源:51cto博客
作者:sailyangfan的空间
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dump备份

restore还原

dd数据备份

mkisofs镜像文件制作

dump备份

dump主要用于备份真个文件系统备份，虽然也可以备份单一目录，但是对目录的支持不足，单一目录还是建议使用打包压缩的方式进行备份

dump另一个只要功能就是制定等级，也就是可以进行增量备份。

dump等级分为0~9 10个等级，0是完全备份，1是在0的基础上进行增量备份，依次类推

当待备份的数据为单一文件系统

可以利用了level 0~9进行备份，同时可以使用dump完整功能

当待备份的数据只是目录，并非单一文件系统

限制：

所有备份数据必须都在该目录下

仅能使用level 0 进行数据备份

不支持-u参数，即无法创建/etc/dumpdates这个level备份的时间记录文件

语法：dump [-Suvj] [-level] [-f备份文件]待备份数据

dump -W

选项与参数：

-S:仅列出后面的待备份数据需要多少磁盘空间才能够备份完毕

-u:将这次备份记录到/etc/dumpdates文件中

-v:将dump文件过程显示出来

-j:加入bzip2的支持，将数据进行压缩，默认压缩等级2

-level:备份等级0~9

-f:备份文件

-W:列出在/etc/fstab里面的具有dump设置的分区是否有过备份

举例1：备份挂载到/boot文件系统 level -0

[root@localhost ~]# dump -S /boot

16752640

[root@localhost ~]# dump -u -0 -f /root/boot.dump.0 /boot

  DUMP: Date of this level 0 dump: Fri Feb 28 15:05:56 2014

  DUMP: Dumping /dev/sda1 (/boot) to /root/boot.dump.0

  DUMP: Label: /boot

  DUMP: Writing 10 Kilobyte records

  DUMP: mapping (Pass I) [regular files]

  DUMP: mapping (Pass II) [directories]

  DUMP: estimated 16360 blocks.

  DUMP: Volume 1 started with block 1 at: Fri Feb 28 15:05:56 2014

  DUMP: dumping (Pass III) [directories]

  DUMP: dumping (Pass IV) [regular files]

  DUMP: Closing /root/boot.dump.0

  DUMP: Volume 1 completed at: Fri Feb 28 15:05:58 2014

  DUMP: Volume 1 16440 blocks (16.05MB)

  DUMP: Volume 1 took 0:00:02

  DUMP: Volume 1 transfer rate: 8220 kB/s

  DUMP: 16440 blocks (16.05MB) on 1 volume(s)

  DUMP: finished in 2 seconds, throughput 8220 kBytes/sec

  DUMP: Date of this level 0 dump: Fri Feb 28 15:05:56 2014

  DUMP: Date this dump completed:  Fri Feb 28 15:05:58 2014

  DUMP: Average transfer rate: 8220 kB/s

  DUMP: DUMP IS DONE

[root@localhost ~]# cat /etc/dumpdates

/dev/sda1 0 Fri Feb 28 15:05:56 2014 +0800

=>可以看出etc/dumpdates记录着这次备份信息

举例2：查看文件系统备份记录

[root@localhost ~]# dump -W

Last dump(s) done (Dump '>' file systems):

> /dev/sda2     (     /) Last dump: never

> /dev/sda3     ( /home) Last dump: never

  /dev/sda1     ( /boot) Last dump: Level 0, Dat

> /dev/sda6     (/mnt/sda6) Last dump: never

=>可以看出sda1已经进行了level0备份，其他还未备份

举例3:增量备份 level 1

[root@localhost ~]# dd if=/dev/zero of=/boot/bigfile.img bs=1M count=20

20+0 records in

20+0 records out

20971520 bytes (21 MB) copied, 0.320717 seconds, 65.4 MB/s

=>先创建一个20M左右的文件

[root@localhost ~]# dump -u -1 -f /root/boot.dump.1 /boot

  DUMP: Date of this level 1 dump: Fri Feb 28 15:17:51 2014

  DUMP: Date of last level 0 dump: Fri Feb 28 15:05:56 2014

  DUMP: Dumping /dev/sda1 (/boot) to /root/boot.dump.1

  DUMP: Label: /boot

  DUMP: Writing 10 Kilobyte records

  DUMP: mapping (Pass I) [regular files]

  DUMP: mapping (Pass II) [directories]

  DUMP: estimated 20543 blocks.

  DUMP: Volume 1 started with block 1 at: Fri Feb 28 15:17:52 2014

  DUMP: dumping (Pass III) [directories]

  DUMP: dumping (Pass IV) [regular files]

  DUMP: Closing /root/boot.dump.1

  DUMP: Volume 1 completed at: Fri Feb 28 15:17:53 2014

  DUMP: Volume 1 20580 blocks (20.10MB)

  DUMP: Volume 1 took 0:00:01

  DUMP: Volume 1 transfer rate: 20580 kB/s

  DUMP: 20580 blocks (20.10MB) on 1 volume(s)

  DUMP: finished in 1 seconds, throughput 20580 kBytes/sec

  DUMP: Date of this level 1 dump: Fri Feb 28 15:17:51 2014

  DUMP: Date this dump completed:  Fri Feb 28 15:17:53 2014

  DUMP: Average transfer rate: 20580 kB/s

  DUMP: DUMP IS DONE

[root@localhost ~]# cat /etc/dumpdates

/dev/sda1 0 Fri Feb 28 15:05:56 2014 +0800

/dev/sda1 1 Fri Feb 28 15:17:51 2014 +0800

=>这次配备写入备份记录中

[root@localhost ~]# dump -W

Last dump(s) done (Dump '>' file systems):

> /dev/sda2     (     /) Last dump: never

> /dev/sda3     ( /home) Last dump: never

  /dev/sda1     ( /boot) Last dump: Level 1, Date Fri Feb 28 15:17:51 2014

> /dev/sda6     (/mnt/sda6) Last dump: never

[root@localhost ~]# ll /root/boot*

-rw-r--r-- 1 root root 16834560 02-28 15:05 /root/boot.dump.0

-rw-r--r-- 1 root root 21073920 02-28 15:17 /root/ boot.dump.1

=> boot.dump.1大小约为20M，可见是增量备份

举例4：单一目录进行备份

[root@localhost ~]# dump -0 -f /root/etc.dump /etc

  DUMP: Date of this level 0 dump: Fri Feb 28 15:23:39 2014

  DUMP: Dumping /dev/sda2 (/ (dir etc)) to /root/etc.dump

DUMP: Label: /

  DUMP: Writing 10 Kilobyte records

  DUMP: mapping (Pass I) [regular files]

  DUMP: mapping (Pass II) [directories]

  DUMP: estimated 177675 blocks.

  DUMP: Volume 1 started with block 1 at: Fri Feb 28 15:23:41 2014

  DUMP: dumping (Pass III) [directories]

  DUMP: dumping (Pass IV) [regular files]

  DUMP: Closing /root/etc.dump

  DUMP: Volume 1 completed at: Fri Feb 28 15:24:23 2014

  DUMP: Volume 1 188600 blocks (184.18MB)

  DUMP: Volume 1 took 0:00:42

  DUMP: Volume 1 transfer rate: 4490 kB/s

  DUMP: 188600 blocks (184.18MB) on 1 volume(s)

  DUMP: finished in 42 seconds, throughput 4490 kBytes/sec

  DUMP: Date of this level 0 dump: Fri Feb 28 15:23:39 2014

  DUMP: Date this dump completed:  Fri Feb 28 15:24:23 2014

  DUMP: Average transfer rate: 4490 kB/s

  DUMP: DUMP IS DONE

[root@localhost ~]# ll /root/etc.dump

-rw-r--r-- 1 root root 193126400 02-28 15:24 /root/etc.dump

restore还原

dump备份的文件由restore进行还原

语法：

查看dump文件：restore –t [-f dumpfile] [-h]

比较dump与实际文件：restore –C [-f dumpfile] –D挂载点

进入互动模式(还原单个文件)：restore –i [-f dumpfile]

还原整个文件系统：restore –r [-f dumpfile]

选项与参数：

相关的各种模式，各种模式无法混用.例如不可以写 -tC

-t:此模式用在察看 dump起来的备份档中含有什么重要数据！类似 tar -t功能；

-C:此模式可以将 dump内的数据拿出来跟实际的文件系统做比较，最终会列出[在 dump文件内有记录的，且目前文件系统不一样]的文件；

-i:进入互动模式，可以仅还原部分文件，用在 dump目录时的还原

-r:将整个 filesystem还原的一种模式，用在还原针对文件系统的 dump备份；

其他较常用到的选项功能：

-h:察看完整备份数据中的 inode与文件系统 label等信息

-f:后面就接你要处理的那个 dump文件

-D:与 -C进行搭配，可以查出后面接的挂载点与 dump内有不同的文件

举例1：查看dump备份文件

[root@localhost ~]# restore -t -f /root/boot.dump.0

Dump   date: Fri Feb 28 15:05:56 2014

Dumped from: the epoch

Level 0 dump of /boot on localhost.localdomain:/dev/sda1

Label: /boot

         2      .

        11      ./lost+found

     10041      ./grub

     10059      ./grub/grub.conf

…….

        14      ./System.map-2.6.18-371.el5

        15      ./config-2.6.18-371.el5

        16      ./symvers-2.6.18-371.el5.gz

        17      ./vmlinuz-2.6.18-371.el5

举例2：比较文件差异

[root@localhost ~]# mv /boot/message /boot/message-back

[root@localhost ~]# restore -C -f /root/boot.dump.0 -D /boot

Dump   date: Fri Feb 28 15:05:56 2014

Dumped from: the epoch

Level 0 dump of /boot on localhost.localdomain:/dev/sda1

Label: /boot

filesys = /boot

restore: unable to stat ./message: No such file or directory

Some files were modified!  1 compare errors

举例3：还原整个文件系统

[root@localhost ~]# dd if=/dev/zero of=/home/newfile bs=1M count=200

200+0 records in

200+0 records out

209715200 bytes (210 MB) copied, 3.83857 seconds, 54.6 MB/s

[root@localhost ~]# mkfs -t ext3 /home/newfile

mke2fs 1.39 (29-May-2006)

/home/newfile is not a block special device.

……

180 days, whichever comes first.  Use tune2fs -c or -i to override.

[root@localhost ~]# mount -o loop /home/newfile /mnt

[root@localhost ~]# df -h

文件系统              容量  已用 可用 已用% 挂载点

/dev/sda2             9.5G  4.4G  4.7G  49% /

/dev/sda3             4.8G  339M  4.2G   8% /home

/dev/sda1              99M   42M   53M  45% /boot

tmpfs                1014M     0 1014M   0% /dev/shm

/home/newfile         194M  5.6M  179M   4% /mnt

=>创建一个文件挂载到mnt下

[root@localhost ~]# cd /mnt

[root@localhost mnt]# restore -r -f /root/boot.dump.0

restore: ./lost+found: File exists

[root@localhost mnt]# ll

总计 16149

-rw-r--r-- 1 root root    70400 10-01 21:10 config-2.6.18-371.el5

drwxr-xr-x 2 root root     1024 02-18 09:51 grub

-rw------- 1 root root  2748313 02-18 09:46 initrd-2.6.18-371.el5.img

drwx------ 2 root root    12288 02-14 18:00 lost+found

-rw-r--r-- 1 root root    80032 2009-03-13 message

-rw------- 1 root root    27676 02-28 15:54 restoresymtable

-rw-r--r-- 1 root root   117436 10-01 21:10 symvers-2.6.18-371.el5.gz

-rw-r--r-- 1 root root   996296 10-01 21:10 System.map-2.6.18-371.el5

-rw-r--r-- 1 root root 10485760 02-28 13:25 testing.img

-rw-r--r-- 1 root root  1912148 10-01 21:10 vmlinuz-2.6.18-371.el5

=>还原level 0备份

[root@localhost mnt]# restore -r -f /root/boot.dump.1

[root@localhost mnt]# ll

总计 36711

-rw-r--r-- 1 root root 20971520 02-28 15:17 bigfile.img

-rw-r--r-- 1 root root    70400 10-01 21:10 config-2.6.18-371.el5

drwxr-xr-x 2 root root     1024 02-18 09:51 grub

-rw------- 1 root root  2748313 02-18 09:46 initrd-2.6.18-371.el5.img

drwx------ 2 root root    12288 02-14 18:00 lost+found

-rw-r--r-- 1 root root    80032 2009-03-13 message

-

------- 1 root root    27724 02-28 15:55 restoresymtable

-rw-r--r-- 1 root root   117436 10-01 21:10 symvers-2.6.18-371.el5.gz

-rw-r--r-- 1 root root   996296 10-01 21:10 System.map-2.6.18-371.el5

-rw-r--r-- 1 root root 10485760 02-28 13:25 testing.img

-rw-r--r-- 1 root root  1912148 10-01 21:10 vmlinuz-2.6.18-371.el5

=>还原level 1备份可以看到多了bigfile.img这个增量文件

dd

dd功能不仅限于创建文件，更多功能在于“备份”，cp,dump只是简单的文件数据拷贝，而dd可以读取设备的所有内容，比如superblock ,boot sector,mete data等

语法：dd if=”input file” of=”output file” bs=”block” count=”number”

选项与参数：

if:输入文件，也可以是设备

of:输出文件，也可以是设备

bs:每个block的大小，默认是512K

count:block数量

举例1.文件备份

[root@localhost ~]# dd if=~/.bashrc of=/tmp/bashrc

0+1 records in

0+1 records out

176 bytes (176 B) copied, 7.3142e-05 seconds, 2.4 MB/s

[root@localhost ~]# ll /tmp/bashrc

-rw-r--r-- 1 root root 176 02-28 16:17 /tmp/bashrc

举例2：文件系统备份

[root@localhost ~]# dd if=/dev/sda1 of=/tmp/boot.dd bs=1M

101+1 records in

101+1 records out

106896384 bytes (107 MB) copied, 9.60492 seconds, 11.1 MB/s

[root@localhost ~]# ll /tmp/boot.dd

-rw-r--r-- 1 root root 106896384 02-28 16:19 /tmp/boot.dd

举例3：文件系统还原

[root@localhost ~]# dd if=/tmp/boot.dd of=/dev/sda1 bs=1M

举例4.文件系统完全复制

Dump备份时，我们需要先用Dump将文件系统备份，然后创建新的文件系统，格式化，再将备份文件还原到新的文件系统。

使用dd可以不用格式化，就可以完全复制一个文件系统，因为dd将uperblock ,boot sector,mete data等信息都进行复制，格式化要做的不也正是这些事吗

[root@bogon ~]# fdisk /dev/sda

…….

Command (m for help): n

……

Command (m for help): P

……

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *           1          13      104391   83  Linux

……

/dev/sda7            2116        2134      152586   83  Linux

Command (m for help): w

……

[root@bogon ~]# partprobe

=>创建完分区

[root@bogon ~]# dd if=/dev/sda1 of=/dev/sda7

208782+0 records in

208782+0 records out

106896384 bytes (107 MB) copied, 23.5363 seconds, 4.5 MB/s

[root@bogon ~]# mount /dev/sda7 /mnt

[root@bogon ~]# ll /mnt

总计 5838

-rw-r--r-- 1 root root   70400 10-01 21:10 config-2.6.18-371.el5

drwxr-xr-x 2 root root    1024 02-18 20:26 grub

-rw------- 1 root root 2748762 02-27 19:45 initrd-2.6.18-371.el5.img

drwx------ 2 root root   12288 02-19 03:59 lost+found

-rw-r--r-- 1 root root   80032 2009-03-13 message

-rw-r--r-- 1 root root  117436 10-01 21:10 symvers-2.6.18-371.el5.gz

-rw-r--r-- 1 root root  996296 10-01 21:10 System.map-2.6.18-371.el5

-rw-r--r-- 1 root root 1912148 10-01 21:10 vmlinuz-2.6.18-371.el5

=> /mnt和/boot下的内容一样 并且没有进行格式化

mkisofs(镜像文件备份)

语法：mkisofs [-o镜像文件] [-rv] [-m file]待备份的文件 [-V vol] –graft-point isodir=sysdir

选项与参数:

-o:镜像文件

-r:产生UNIX/Linux支持的文件数据

-v:显示构建ISO的过程

-m:排除的文件

-V:卷标名称

-graft-point:目录对照名称，如果不进行指定所以的信息都会保持在根目录

举例：

[root@bogon ~]# mkisofs -o /tmp/system.img -r -m /home/lost+found -V 'tkf_file' -graft-point /root=/root /home=/home /etc=/etc

[root@bogon ~]# mount -o loop /tmp/system.img /mnt

[root@bogon ~]# ll /mnt

dr-xr-xr-x 114 root root 34816 03-01 14:31 etc

dr-xr-xr-x   3 root root  2048 03-01 14:31 home

dr-xr-xr-x  18 root root  4096 03-01 14:31 root