dump备份及还原 dump备份及还原

完整备份工具dump及restore还原
备份整个文件系统
备份目录

dump备份
原理：通过指定level来实现完整备份和差异备份，第一次备份时使用的是level0，即完整备份，第二次备份时，指定level1，和level0比较只备份有差异的部分

备份文件系统
【dump备份及还原】单一的文件系统可以使用完整的dump功能，包括使用全部0~9level，也可以使用挂载点或设备名来备份（如：/dev/sda1）

备份目录
如仅备份/home/pyz，而非独立文件系统，此时备份有限制：
1.所有备份数据必须要在该目录下
2.仅能使用level0，即仅支持完整备份
3.不支持-u选项，即不能建立/etc/dumpdates文件来记录各level备份的时间

用法：

[root@instructor~]#dump [-Suvj] [-level] [-f 备份文件名] 等待备份文件

参数：
-S：显示待备份文件需要占用的磁盘空间
-u：将这次dump的时间记录到/etc/dumpdates文件中
-v：显示详细的备份过程
-j：将备份文件使用bzip2压缩，默认压缩等级为2
-level：备份级别，0~9
-f：后接备份后的文件名
例：备份系统中最小的文件系统
1.先找出系统中最小的文件系统

[root@instructor ~]# df -h FilesystemSizeUsed Avail Use% Mounted on /dev/mapper/vg_instructor-lv_root 7.5G6.9G 486M94% / tmpfs504M112K 504M1% /dev/shm /dev/sda1485M32M 428M7% /boot /dev/sdb1485M11M 449M3% /mnt/new /dev/sdb297M16M77M17% /mnt/test

这里最小的就是/dev/sdb2
2.测试一下，备份/dev/sdb2需要多大空间

[root@instructor ~]# dump -S /dev/sdb2 10537984//大概需要10M左右

3.将/dev/sdb2完整备份到/tmp/test下，命名为test.dump，同时更新记录文件

[root@instructor test]# dump -0u -f/tmp/test/test.dump /mnt/test DUMP: Date of this level 0 dump: Wed Oct 8 11:20:08 2014//记录等级与备份时间 DUMP: Dumping /dev/sdb2 (/mnt/test) to /tmp/test/test.dump//来源与目标 DUMP: Label: test DUMP: Writing 10 Kilobyte records DUMP: mapping (Pass I) [regular files] DUMP: mapping (Pass II) [directories] DUMP: estimated 10291 blocks. DUMP: Volume 1 started with block 1 at: Wed Oct8 11:20:08 2014 DUMP: dumping (Pass III) [directories] DUMP: dumping (Pass IV) [regular files] DUMP: Closing /tmp/test/test.dump DUMP: Volume 1 completed at: Wed Oct 8 11:20:08 2014 DUMP: Volume 1 10310 blocks (10.07MB) DUMP: 10310 blocks (10.07MB) on 1 volume(s) DUMP:finished in less than a second DUMP: Date of this level 0 dump: Wed Oct 8 11:20:08 2014 DUMP: Date this dump completed: Wed Oct8 11:20:08 2014 DUMP: Average transfer rate: 0 kB/s DUMP: DUMP IS DONE

4.查看系统中建立的记录

[root@instructor test]# cat /etc/dumpdates /dev/sdb2 0 Wed Oct8 11:20:08 2014 +0800

查看被dump过的文件系统

[root@instructor test]# dump -W Last dump(s) done (Dump '>' filesystems): > /dev/mapper/vg_instructor-lv_root(/) Last dump: never > /dev/sda1( /boot) Last dump: never /dev/sdb1(/mnt/new) Lastdump: never /dev/sdb2(/mnt/test) Lastdump: Level 0, Date Wed Oct8 11:20:082014

显示/dev/sdb2备份过

例：差异备份
1.在/dev/sdb2即/mnt/test中创建一个约10M的文件

[root@instructor test]# dd if=/dev/zeroof=/mnt/test/testing.img bs=1M count=10 10+0 records in 10+0 records out 10485760 bytes (10 MB) copied, 0.0893004 s,117 MB/s

2.开始差异备份

[root@instructor test]# dump -1u -f/tmp/test/test.dump.1 /mnt/test DUMP: Date of this level 1 dump: Wed Oct 8 11:31:13 2014 DUMP: Date of last level 0 dump: Wed Oct 8 11:20:08 2014 DUMP: Dumping /dev/sdb2 (/mnt/test) to /tmp/test/test.dump.1 DUMP: Label: test DUMP: Writing 10 Kilobyte records DUMP: mapping (Pass I) [regular files] DUMP: mapping (Pass II) [directories] DUMP: estimated 10283 blocks. DUMP: Volume 1 started with block 1 at: Wed Oct8 11:31:13 2014 DUMP: dumping (Pass III) [directories] DUMP: dumping (Pass IV) [regular files] DUMP: Closing /tmp/test/test.dump.1 DUMP: Volume 1 completed at: Wed Oct 8 11:31:13 2014 DUMP: Volume 1 10300 blocks (10.06MB) DUMP: 10300 blocks (10.06MB) on 1 volume(s) DUMP: finished in less than a second DUMP: Date of this level 1 dump: Wed Oct 8 11:31:13 2014 DUMP: Date this dump completed: Wed Oct8 11:31:13 2014 DUMP: Average transfer rate: 0 kB/s DUMP: DUMP IS DONE

3.查看是否有level1的记录

[root@instructor test]# cat /etc/dumpdates /dev/sdb2 0 Wed Oct8 11:20:08 2014 +0800 /dev/sdb2 1 Wed Oct8 11:31:13 2014 +0800

例：用dump备份目录（非文件系统），并且压缩

[root@instructor test]# dump -0j -f/tmp/test/etc.dump.bz2 /etc DUMP: Date of this level 0 dump: Wed Oct 8 11:50:16 2014 DUMP: Dumping /dev/mapper/vg_instructor-lv_root (/ (dir etc)) to/tmp/test/etc.dump.bz2 DUMP: Label: none DUMP: Writing 10 Kilobyte records DUMP:Compressing output at compression level 2 (bzlib) DUMP: mapping (Pass I) [regular files] DUMP: mapping (Pass II) [directories] DUMP: estimated 75521 blocks. DUMP: Volume 1 started with block 1 at: Wed Oct8 11:50:18 2014 DUMP: dumping (Pass III) [directories] DUMP: dumping (Pass IV) [regular files] DUMP: Closing /tmp/test/etc.dump.bz2 DUMP: Volume 1 completed at: Wed Oct 8 11:51:11 2014 DUMP: Volume 1 took 0:00:53 DUMP: Volume 1 transfer rate: 424 kB/s DUMP: Volume 1 86570kB uncompressed, 22492kB compressed, 3.849:1 DUMP: 86570 blocks (84.54MB) on 1 volume(s) DUMP: finished in 53 seconds, throughput 1633 kBytes/sec DUMP: Date of this level 0 dump: Wed Oct 8 11:50:16 2014 DUMP: Date this dump completed: Wed Oct8 11:51:11 2014 DUMP: Average transfer rate: 424 kB/s DUMP: Wrote 86570kB uncompressed, 22492kB compressed, 3.849:1 DUMP: DUMP IS DONE

dump默认不包含压缩功能，加了-j参数后可以使用bzip2进行压缩

restore还原
用法：

[root@instructortest]# restore -t [-f dumpfile] [-h]查看dump文件 [root@instructor test]# restore -C [-fdumpfile] [-D 挂载点]比较dump与原文件 [root@instructor test]# restore -i [-fdumpfile]互动模式 [root@instructor test]# restore -r [-fdumpfile]还原整个文件系统

参数：
-t：查看dump备份文件内容
-C：dump后的文件和原文件作对比
-i：互动模式，可以仅还原部分文件，用于还原备份目录的文件
-r：还原整个文件系统
-h：查看完整备份中的inode与文件系统label信息
-f：后面跟要处理的dump文件
-D：与-C进行搭配，可以查出后面挂载点与原文件的区别
例：用restore查看dump后的备份数据

[root@instructor test]# restore -t -f/tmp/test/etc.dump.bz2

比较备份文件与原文件的差异

[root@instructor test]# cd /mnt/test [root@instructor test]# mv testing.imgtesting.img.bak [root@instructor test]# restore -C -f/tmp/test/test.dump.1 Dumpdate: Wed Oct8 11:31:13 2014 Dumped from: Wed Oct8 11:20:08 2014 Level 1 dump of /mnt/test oninstructor:/dev/sdb2 Label: test filesys = /mnt/test restore:unable to stat ./testing.img: No such file or directory Somefiles were modified!1 compare errors

还原整个文件系统
前提：先新建文件系统并将其挂载，然后进入到挂载点下面执行