一、命令简介
Linux dump命令用于备份文件系统。dump为备份工具程序，可将目录或整个文件系统备份至指定的设备，或备份成一个大文件。dump命令只可以备份ext2/3/4格式的文件系统，centos7默认未安装dump命令，可以使用yum install -y dump安装此命令。
二、使用示例
1、全量备份/boot分区
[root@bunian ~]# dump -0uj -f /root/boot.bak.bz2 /boot/
DUMP: Date of this level 0 dump: Fri Jul 30 16:10:06 2021
DUMP: Dumping /dev/sda1 (/boot) to /root/boot.bak.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 115437 blocks.
DUMP: Volume 1 started with block 1 at: Fri Jul 30 16:10:06 2021
DUMP: dumping (Pass III) [directories]
DUMP: dumping (Pass IV) [regular files]
DUMP: Closing /root/boot.bak.bz2
DUMP: Volume 1 completed at: Fri Jul 30 16:10:22 2021
DUMP: Volume 1 took 0:00:16
DUMP: Volume 1 transfer rate: 6656 kB/s
DUMP: Volume 1 116040kB uncompressed, 106506kB compressed, 1.090:1
DUMP: 116040 blocks (113.32MB) on 1 volume(s)
DUMP: finished in 16 seconds, throughput 7252 kBytes/sec
DUMP: Date of this level 0 dump: Fri Jul 30 16:10:06 2021
DUMP: Date this dump completed: Fri Jul 30 16:10:22 2021
DUMP: Average transfer rate: 6656 kB/s
DUMP: Wrote 116040kB uncompressed, 106506kB compressed, 1.090:1
DUMP: DUMP IS DONE
[root@bunian ~]# ll -h /root/
总用量 105M
-rw-------. 1 root root 1.8K 7月 30 16:03 anaconda-ks.cfg
-rw-r–r--. 1 root root 105M 7月 30 16:10 boot.bak.bz2
[root@bunian ~]# df -hT
文件系统 类型 容量 已用 可用 已用% 挂载点
/dev/mapper/centos-root ext4 9.8G 1.2G 8.1G 13% /
devtmpfs devtmpfs 908M 0 908M 0% /dev
tmpfs tmpfs 919M 0 919M 0% /dev/shm
tmpfs tmpfs 919M 8.5M 911M 1% /run
tmpfs tmpfs 919M 0 919M 0% /sys/fs/cgroup
/dev/sda1 ext4 976M 115M 795M 13% /boot
/dev/mapper/centos-home ext4 17G 45M 16G 1% /home
tmpfs tmpfs 184M 0 184M 0% /run/user/02、增量备份/boot分区
在/boot分区创建一个测试文件hi.txt
[root@bunian ~]# cd /boot/
[root@bunian boot]# touch hi.txt
[root@bunian boot]# echo “this is a test” > hi.txt然后增量备份/boot分区
[root@bunian ~]# dump -1uj -f /root/boot.bak1.bz2 /boot/
DUMP: Date of this level 1 dump: Fri Jul 30 16:17:15 2021
DUMP: Date of last level 0 dump: Fri Jul 30 16:16:41 2021
DUMP: Dumping /dev/sda1 (/boot) to /root/boot.bak1.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 39 blocks.
DUMP: Volume 1 started with block 1 at: Fri Jul 30 16:17:15 2021
DUMP: dumping (Pass III) [directories]
DUMP: dumping (Pass IV) [regular files]
DUMP: Closing /root/boot.bak1.bz2
DUMP: Volume 1 completed at: Fri Jul 30 16:17:15 2021
DUMP: 40 blocks (0.04MB) on 1 volume(s)
DUMP: finished in less than a second
DUMP: Date of this level 1 dump: Fri Jul 30 16:17:15 2021
DUMP: Date this dump completed: Fri Jul 30 16:17:15 2021
DUMP: Average transfer rate: 0 kB/s
DUMP: Wrote 40kB uncompressed, 11kB compressed, 3.637:1
DUMP: DUMP IS DONE查看增量备份文件大小
[root@bunian ~]# ll -h /root
总用量 105M
-rw-------. 1 root root 1.8K 7月 30 16:03 anaconda-ks.cfg
-rw-r–r--. 1 root root 12K 7月 30 16:17 boot.bak1.bz2
-rw-r–r--. 1 root root 105M 7月 30 16:10 boot.bak.bz23、查询分区的最新备份记录
[root@bunian ~]# dump -W
Last dump(s) done (Dump ‘>’ file systems):
/dev/mapper/centos-root ( /) Last dump: never
/dev/sda1 ( /boot) Last dump: Level 1, Date Fri Jul 30 16:17:15 2021
/dev/mapper/centos-home ( /home) Last dump: never4、备份文件或目录
备份文件和目录只能使用0级别，即只能全量备份。
[root@bunian ~]# dump -0j -f /home/etc.dump.bz2 /etc/
DUMP: Date of this level 0 dump: Fri Jul 30 16:23:29 2021
DUMP: Dumping /dev/mapper/centos-root (/ (dir etc)) to /home/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 35010 blocks.
DUMP: Volume 1 started with block 1 at: Fri Jul 30 16:23:30 2021
DUMP: dumping (Pass III) [directories]
DUMP: dumping (Pass IV) [regular files]
DUMP: Closing /home/etc.dump.bz2
DUMP: Volume 1 completed at: Fri Jul 30 16:23:35 2021
DUMP: Volume 1 took 0:00:05
DUMP: Volume 1 transfer rate: 2470 kB/s
DUMP: Volume 1 39190kB uncompressed, 12350kB compressed, 3.174:1
DUMP: 39190 blocks (38.27MB) on 1 volume(s)
DUMP: finished in 5 seconds, throughput 7838 kBytes/sec
DUMP: Date of this level 0 dump: Fri Jul 30 16:23:29 2021
DUMP: Date this dump completed: Fri Jul 30 16:23:35 2021
DUMP: Average transfer rate: 2470 kB/s
DUMP: Wrote 39190kB uncompressed, 12350kB compressed, 3.174:1
DUMP: DUMP IS DONE三、使用语法及参数说明
1、使用语法
#dump [参数]2、参数说明
| 常用参数 | 参数说明 |
|---|---|
| -0123456789 | 备份的层级 |
| -b | 指定区块的大小，单位为KB |
| -B | 指定备份卷册的区块数目 |
| -c | 修改备份磁带预设的密度与容量 |
| -d | 设置磁带的密度。单位为BPI |
| -f | 指定备份设备 |
| -h | 当备份层级等于或大于指定的层级时，将不备份用户标示为”nodump”的文件 |
| -j | 使用bzlib库压缩备份文件 |
| -n | 当备份工作需要管理员介入时，向所有”operator”群组中的使用者发出通 |
| -s | 备份磁带的长度，单位为英尺 |
| -T | 指定开始备份的时间与日期 |
| -u | 备份完毕后，在/etc/dumpdates中记录备份的文件系统，层级，日期与时间等 |
| -w | 与-W类似，但仅显示需要备份的文件 |
| -W | 显示需要备份的文件及其最后一次备份的层级，时间与日期 |
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