# XFS 文件系统的备份与还原
使用 tar 通常是针对目录树系统来进行备份的工作，如果是针对整个文件系统来进行备份与还原。在 CentOS 7 中可以使用 xfsdump 与 xfsrestore 指令来进行
# XFS 文件系统备份 xfsdump
支持的功能：
全量备份：完整备份文件系统（full backup）
增量备份：Incremental backup
第一次全量备份之后，就可以选择增量备份了
增量备份的差异文件存放在 /var/lib/xfsdump/inventory 中
xfsdump 有如下限制：
- 不支持没有挂载的文件系统备份，所以只能备份已挂载的
- 必须使用 root 的权限才能操作，涉及文件系统的关系
- 只能备份 XFS 文件系统
- 备份下来的数据（文件或存储媒体）只能让 xfsrestore 解析
- 是通过文件系统的 UUID 来分辨各个备份档的，因此不能备份两个具有相同 UUID 的文件系统
简单操作时的语法如下（完整的选项非常复杂）
xfsdump [-L S_label][-M M_label][-l #][-f 备份档] 带备份资料
xfsdump -I
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选项与参数：
- L：xfsdump 会记录每次备份的 session 标头，这里可以填写针对此文件系统的建议说明
- M：xfsdump 可以记录存储媒体的标头，这里可以填写此媒体的建议说明
- l：小写的 L，指定等级。有 0~9 共 10 个等级，预设为 0 完整备份
- f：有点类似 tar，后面接产生的文件，例如 /dev/st0 装置文件名或其他一般文件名等
- I：从 /var/lib/xfsdump/inventory 列出目前备份的信息状态
注意：xfsdump 预设仅支持文件系统的备份，并不支持目录的备份。如 /etc 不是一个独立的文件系统
# 用 xfsdump 备份完整的文件系统
# 1. 先确定 /boot 是独立的问价系统
[mrcode@study ~]$ df -h /boot/
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 1014M 171M 844M 17% /boot
# 挂载点是 /boot 文件系统是 /dev/sda2 装置，是独立的文件系统
# 2. 将完整备份的文件名记录为 /srv/boot.dump
# 指定了一个等级0，后面 lm 都是说明，后面是要保存的文件地址，最后是要备份的装置
[root@study ~]# xfsdump -l 0 -L boot_all -M boot_all -f /srv/boot.dump /boot
xfsdump: using file dump (drive_simple) strategy
xfsdump: version 3.1.7 (dump format 3.0) - type ^C for status and control
xfsdump: level 0 dump of study.centos.mrcode:/boot # level 0 开始备份本机 /boot 系统
xfsdump: dump date: Tue Oct 29 03:03:50 2019 # 备份时间
xfsdump: session id: 49ac1ac5-c63b-4778-9b87-f77f3b1d703a # dump 的 ID
xfsdump: session label: "boot_all" # 上面写的说明
xfsdump: ino map phase 1: constructing initial dump list # 开始备份
xfsdump: ino map phase 2: skipping (no pruning necessary)
xfsdump: ino map phase 3: skipping (only one dump stream)
xfsdump: ino map construction complete
xfsdump: estimated dump size: 144381568 bytes
xfsdump: /var/lib/xfsdump/inventory created
xfsdump: creating dump session media file 0 (media 0, file 0)
xfsdump: dumping ino map
xfsdump: dumping directories
xfsdump: dumping non-directory files
xfsdump: ending media file
xfsdump: media file size 144048736 bytes
xfsdump: dump size (non-dir files) : 143807160 bytes
xfsdump: dump complete: 1 seconds elapsed
xfsdump: Dump Summary:
xfsdump: stream 0 /srv/boot.dump OK (success)
xfsdump: Dump Status: SUCCESS
# 如果不在指令中增加 -L 和 -M 会进入互动模式，让你手动填写确认后才会开始备份
[root@study ~]# ll /srv/boot.dump
-rw-r--r--. 1 root root 144048736 10月 29 03:03 /srv/boot.dump
[root@study ~]# ll /var/lib/xfsdump/inventory/
总用量 16
-rw-r--r--. 1 root root 312 10月 29 03:03 13d0663f-4cbd-412d-aa9f-975eb18da590.InvIndex
-rw-r--r--. 1 root root 5080 10月 29 03:03 6ad3d9fa-9c06-4968-9250-c1a70b5629ed.StObj
-rw-r--r--. 1 root root 576 10月 29 03:03 fstab
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# 用 xfsdump 进行增量备份（Incremental backups）
增量是在全量的基础上，也就是至少有 level 0 ，才能够几区有其他的增量备份（1~9）
# 查看 xfsdump 信息
[root@study ~]# xfsdump -I
file system 0:
fs id: 13d0663f-4cbd-412d-aa9f-975eb18da590
session 0:
mount point: study.centos.mrcode:/boot
device: study.centos.mrcode:/dev/sda2
time: Tue Oct 29 03:03:50 2019
session label: "boot_all"
session id: 49ac1ac5-c63b-4778-9b87-f77f3b1d703a
level: 0
resumed: NO
subtree: NO
streams: 1
stream 0:
pathname: /srv/boot.dump
start: ino 69 offset 0
end: ino 1577745 offset 0
interrupted: NO
media files: 1
media file 0:
mfile index: 0
mfile type: data
mfile size: 144048736
mfile start: ino 69 offset 0
mfile end: ino 1577745 offset 0
media label: "boot_all"
media id: da10035c-1c0b-4773-a56e-409a17fe9913
xfsdump: Dump Status: SUCCESS
# 可以看到，有一个 level 0
# 下面先在 boot 中建立一个大约 10MB 的文件
[root@study ~]# dd if=/dev/zero of=/boot/testing.img bs=1M count=10
记录了10+0 的读入
记录了10+0 的写出
10485760字节(10 MB)已复制，0.00396854 秒，2.6 GB/秒
# 2. 建立差异备份，这里使用 -l 1 指定了 level 1 的被增量备份
[root@study ~]# dd if=/dev/zero of=/boot/testing.img bs=1M count=10
记录了10+0 的读入
记录了10+0 的写出
10485760字节(10 MB)已复制，0.00396854 秒，2.6 GB/秒
[root@study ~]# xfsdump -l 1 -L boot_2 -M boot_2 -f /srv/boot.dump1 /boot
xfsdump: using file dump (drive_simple) strategy
xfsdump: version 3.1.7 (dump format 3.0) - type ^C for status and control
xfsdump: level 1 incremental dump of study.centos.mrcode:/boot based on level 0 dump begun Tue Oct 29 03:03:50 2019
xfsdump: dump date: Tue Oct 29 03:11:00 2019
xfsdump: session id: 8a8a1680-2a91-4292-943d-0d0a51fa2d67
xfsdump: session label: "boot_2"
xfsdump: ino map phase 1: constructing initial dump list
xfsdump: ino map phase 2: pruning unneeded subtrees
xfsdump: ino map phase 3: skipping (only one dump stream)
xfsdump: ino map construction complete
xfsdump: estimated dump size: 10506880 bytes
xfsdump: creating dump session media file 0 (media 0, file 0)
xfsdump: dumping ino map
xfsdump: dumping directories
xfsdump: dumping non-directory files
xfsdump: ending media file
xfsdump: media file size 10510952 bytes
xfsdump: dump size (non-dir files) : 10488408 bytes
xfsdump: dump complete: 0 seconds elapsed
xfsdump: Dump Summary:
xfsdump: stream 0 /srv/boot.dump1 OK (success)
xfsdump: Dump Status: SUCCESS
[root@study ~]# ll -h /srv/boot*
-rw-r--r--. 1 root root 138M 10月 29 03:03 /srv/boot.dump
-rw-r--r--. 1 root root 11M 10月 29 03:11 /srv/boot.dump1
# 3. 最后再观察下备份情况
[root@study ~]# xfsdump -I
file system 0:
fs id: 13d0663f-4cbd-412d-aa9f-975eb18da590
session 0:
mount point: study.centos.mrcode:/boot
device: study.centos.mrcode:/dev/sda2
time: Tue Oct 29 03:03:50 2019
session label: "boot_all"
session id: 49ac1ac5-c63b-4778-9b87-f77f3b1d703a
level: 0
resumed: NO
subtree: NO
streams: 1
stream 0:
pathname: /srv/boot.dump
start: ino 69 offset 0
end: ino 1577745 offset 0
interrupted: NO
media files: 1
media file 0:
mfile index: 0
mfile type: data
mfile size: 144048736
mfile start: ino 69 offset 0
mfile end: ino 1577745 offset 0
media label: "boot_all"
media id: da10035c-1c0b-4773-a56e-409a17fe9913
session 1:
mount point: study.centos.mrcode:/boot
device: study.centos.mrcode:/dev/sda2
time: Tue Oct 29 03:11:00 2019
session label: "boot_2"
session id: 8a8a1680-2a91-4292-943d-0d0a51fa2d67
level: 1
resumed: NO
subtree: NO
streams: 1
stream 0:
pathname: /srv/boot.dump1
start: ino 113 offset 0
end: ino 114 offset 0
interrupted: NO
media files: 1
media file 0:
mfile index: 0
mfile type: data
mfile size: 10510952
mfile start: ino 113 offset 0
mfile end: ino 114 offset 0
media label: "boot_2"
media id: 2c0d4e02-11cd-45a4-b131-8bc6505403fe
xfsdump: Dump Status: SUCCESS
# 可以看到上面出现了 session 1 和 level 1
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# XFS 文件系统还原 xfsrestore
备份文件就是在急用时可以还原系统的重要数据，用 xfsdump 备份的数据可以使用 xfsresotre 来还原
xfsrestore -I # 观察备份文件资料
xfsrestore [-f 备份文件名][-L S_label][-s] 待复原的目录 # 单一文件全系统复原
xfsrestore [-f 备份文件名] -r 待复原目录 # 通过增量备份文件复原系统
xfsrestore [-f 备份文件名] -i 待复原目录 # 进入互动模式
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选项与参数：
- I：与 xfsdump 相同的输出
- f：后面接的就是备份的文件，企业界可能会接 /dev/st0 等磁带机，我们这里接文件名
- L：session 的 label name ，就是在 -I 输出中查询到的数据
- s：需要接特定目录，复原某一个文件或目录的意思
- r：如果是用文件来存储备份数据，这个选项就不需要使用。如果是一个磁带内有多个文件，需要这东西来达成增量复原
- i：进入互动模式，进阶管理员使用的，一般我们不太需要操作它
# 用 xfsrestore 观察 xfsdump 后的备份数据内容
[root@study ~]# xfsrestore -I
file system 0:
fs id: 13d0663f-4cbd-412d-aa9f-975eb18da590
session 0:
mount point: study.centos.mrcode:/boot
device: study.centos.mrcode:/dev/sda2
time: Tue Oct 29 03:03:50 2019
session label: "boot_all"
session id: 49ac1ac5-c63b-4778-9b87-f77f3b1d703a
level: 0
resumed: NO
subtree: NO
streams: 1
stream 0:
pathname: /srv/boot.dump
start: ino 69 offset 0
end: ino 1577745 offset 0
interrupted: NO
media files: 1
media file 0:
mfile index: 0
mfile type: data
mfile size: 144048736
mfile start: ino 69 offset 0
mfile end: ino 1577745 offset 0
media label: "boot_all"
media id: da10035c-1c0b-4773-a56e-409a17fe9913
session 1:
mount point: study.centos.mrcode:/boot
device: study.centos.mrcode:/dev/sda2
time: Tue Oct 29 03:11:00 2019
session label: "boot_2"
session id: 8a8a1680-2a91-4292-943d-0d0a51fa2d67
level: 1
resumed: NO
subtree: NO
streams: 1
stream 0:
pathname: /srv/boot.dump1
start: ino 113 offset 0
end: ino 114 offset 0
interrupted: NO
media files: 1
media file 0:
mfile index: 0
mfile type: data
mfile size: 10510952
mfile start: ino 113 offset 0
mfile end: ino 114 offset 0
media label: "boot_2"
media id: 2c0d4e02-11cd-45a4-b131-8bc6505403fe
xfsrestore: Restore Status: SUCCESS
# 和前面输出的一样
# 这里重点是看到这个文件系统是 /boot 挂载点，有两个备份 level 0 和 level 1
# 可以看到这两个备份文件的大小，更重要的是 session label
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# 简单复原 level 0 的文件系统
# 1. 直接将数据覆盖回去即可
# 这里使用了 -L 就是那个 session label
[root@study ~]# xfsrestore -f /srv/boot.dump -L boot_all /boot
xfsrestore: using file dump (drive_simple) strategy
xfsrestore: version 3.1.7 (dump format 3.0) - type ^C for status and control
xfsrestore: using online session inventory
xfsrestore: searching media for directory dump
xfsrestore: examining media file 0
xfsrestore: reading directories
xfsrestore: 11 directories and 337 entries processed
xfsrestore: directory post-processing
xfsrestore: restoring non-directory files
xfsrestore: restore complete: 0 seconds elapsed
xfsrestore: Restore Summary:
xfsrestore: stream 0 /srv/boot.dump OK (success)
xfsrestore: Restore Status: SUCCESS
# 2. 将备份资料在 /tmp/boot 下解开
[root@study ~]# mkdir /tmp/boot
[root@study ~]# xfsrestore -f /srv/boot.dump -L boot_all /tmp/boot/
xfsrestore: using file dump (drive_simple) strategy
xfsrestore: version 3.1.7 (dump format 3.0) - type ^C for status and control
xfsrestore: using online session inventory
xfsrestore: searching media for directory dump
xfsrestore: examining media file 0
xfsrestore: reading directories
xfsrestore: 11 directories and 337 entries processed
xfsrestore: directory post-processing
xfsrestore: restoring non-directory files
xfsrestore: restore complete: 0 seconds elapsed
xfsrestore: Restore Summary:
xfsrestore: stream 0 /srv/boot.dump OK (success)
xfsrestore: Restore Status: SUCCESS
# 看到两个大小不一致
[root@study ~]# du -sm /boot/ /tmp/boot/
148 /boot/
138 /tmp/boot/
# 对比下发现 /boot 下多了一个 testing.img
[root@study ~]# diff -r /boot/ /tmp/boot/
只在 /boot/ 存在：testing.img
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这里注意了，笔者以为这样复原之后，会完全还原到复原之前的内容的，这里的规则是：同名的文件被覆盖，其他系统内的新的问价会被保留
# 3. 仅复原备份档内的 grub2 到 /tmp/boot2 里面去
[root@study ~]# mkdir /tmp/boot2
[root@study ~]# xfsrestore -f /srv/boot.dump -L boot_all -s grub2 /tmp/boot2
xfsrestore: using file dump (drive_simple) strategy
xfsrestore: version 3.1.7 (dump format 3.0) - type ^C for status and control
xfsrestore: using online session inventory
xfsrestore: searching media for directory dump
xfsrestore: examining media file 0
xfsrestore: reading directories
xfsrestore: 11 directories and 337 entries processed
xfsrestore: directory post-processing
xfsrestore: restoring non-directory files
xfsrestore: restore complete: 0 seconds elapsed
xfsrestore: Restore Summary:
xfsrestore: stream 0 /srv/boot.dump OK (success)
xfsrestore: Restore Status: SUCCESS
[root@study ~]# ll -h /tmp/boot2/
总用量 0
drwx------. 5 root root 97 10月 4 18:32 grub2
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# 复原增量备份资料
增量还原有顺序，比如由 level 0 -> level1 -> level2 那么还原的时候，也需要按照这个顺序
[root@study ~]# xfsrestore -f /srv/boot.dump1 /tmp/boot
xfsrestore: using file dump (drive_simple) strategy
xfsrestore: version 3.1.7 (dump format 3.0) - type ^C for status and control
xfsrestore: searching media for dump
xfsrestore: examining media file 0
xfsrestore: dump description:
xfsrestore: hostname: study.centos.mrcode
xfsrestore: mount point: /boot
xfsrestore: volume: /dev/sda2
xfsrestore: session time: Tue Oct 29 03:11:00 2019
xfsrestore: level: 1
xfsrestore: session label: "boot_2"
xfsrestore: media label: "boot_2"
xfsrestore: file system id: 13d0663f-4cbd-412d-aa9f-975eb18da590
xfsrestore: session id: 8a8a1680-2a91-4292-943d-0d0a51fa2d67
xfsrestore: media id: 2c0d4e02-11cd-45a4-b131-8bc6505403fe
xfsrestore: using online session inventory
xfsrestore: searching media for directory dump
xfsrestore: reading directories
xfsrestore: 1 directories and 12 entries processed
xfsrestore: directory post-processing
xfsrestore: restoring non-directory files
xfsrestore: restore complete: 0 seconds elapsed
xfsrestore: Restore Summary:
xfsrestore: stream 0 /srv/boot.dump1 OK (success)
xfsrestore: Restore Status: SUCCESS
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# 仅还原部分文件的 xfsrestore 互动模式
使用 -s 参数可以接部分数据来还原，当文件太多时，又不知道里面有哪些文件，可以使用互动模式，比如想要知道 level0 的备份数据里面有哪些东西
[root@study ~]# xfsrestore -f /srv/boot.dump -i /tmp/boot3
xfsrestore: using file dump (drive_simple) strategy
xfsrestore: version 3.1.7 (dump format 3.0) - type ^C for status and control
xfsrestore: searching media for dump
xfsrestore: examining media file 0
xfsrestore: dump description:
xfsrestore: hostname: study.centos.mrcode
xfsrestore: mount point: /boot
xfsrestore: volume: /dev/sda2
xfsrestore: session time: Tue Oct 29 03:03:50 2019
xfsrestore: level: 0
xfsrestore: session label: "boot_all"
xfsrestore: media label: "boot_all"
xfsrestore: file system id: 13d0663f-4cbd-412d-aa9f-975eb18da590
xfsrestore: session id: 49ac1ac5-c63b-4778-9b87-f77f3b1d703a
xfsrestore: media id: da10035c-1c0b-4773-a56e-409a17fe9913
xfsrestore: using online session inventory
xfsrestore: searching media for directory dump
xfsrestore: reading directories
xfsrestore: 11 directories and 337 entries processed
xfsrestore: directory post-processing
========================== subtree selection dialog ==========================
the following commands are available:
pwd
ls [ <path> ]
cd [ <path> ]
add [ <path> ] # 可以加入还原文件列表中
delete [ <path> ] # 从还原列表中删除文件，不是删除，只是从列表中移出去
extract # 开始还原动作
quit
help
-> ls # ls 查看有哪些文档
75 initramfs-3.10.0-1062.el7.x86_64.img
77 vmlinuz-0-rescue-f228ab37c368416c84c6b27971ba45a9
76 initramfs-0-rescue-f228ab37c368416c84c6b27971ba45a9.img
74 vmlinuz-3.10.0-1062.el7.x86_64
73 symvers-3.10.0-1062.el7.x86_64.gz
72 config-3.10.0-1062.el7.x86_64
71 System.map-3.10.0-1062.el7.x86_64
70 .vmlinuz-3.10.0-1062.el7.x86_64.hmac
68 grub/
1572928 grub2/
67 efi/
-> add grub/
-> add grub2/
-> add config-3.10.0-229.el7.x86_64
config-3.10.0-229.el7.x86_64 not found # 这个里面不能按退格键，我输出了，不过提示未找到
-> extract
--------------------------------- end dialog ---------------------------------
xfsrestore: restoring non-directory files
xfsrestore: restore complete: 182 seconds elapsed
xfsrestore: Restore Summary:
xfsrestore: stream 0 /srv/boot.dump OK (success)
xfsrestore: Restore Status: SUCCESS
# 查看还原的目录下，的确只有我们需要的两个
[root@study ~]# ls -l /tmp/boot3
总用量 0
drwxr-xr-x. 2 root root 27 10月 4 18:22 grub
drwx------. 5 root root 97 10月 4 18:32 grub2
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