文件备份|还原
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