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1、添加新硬盘用于练习分区
操作注意：
1）先给Linux虚拟机断电
2）虚拟机设置选项，选择添加硬盘，完成后，重启，
3）查询当前配置
[root@localhost ~]# fdisk -l
Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000e9453
Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 64 2611 20458496 8e Linux LVM
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/VolGroup-lv_root: 18.8 GB, 18798870528 bytes
255 heads, 63 sectors/track, 2285 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/VolGroup-lv_swap: 2147 MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
如上，发现新增的硬盘被识别了
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
3、使用fdisk 命令分区
[root@localhost ~]# fdisk /dev/sdb
注意fdisk交互指令说明
| 命令 | 说明 |
| a | 设置可引导标记 |
| b | 编辑bsd磁盘标签 |
| c | 设置DOS操作系统兼容标记 |
| d | 删除一个分区 |
| l | 显示已知的文件系统类型。82为Linux swap分区，83为Linux分区 |
| m | 显示帮助菜单 |
| n | 新建分区 |
| o | 建立空白DOS分区表 |
| p | 显示分区列表 |
| q | 不保存退出 |
| s | 新建空白SUN磁盘标签 |
| t | 改变一个分区的系统ID |
| u | 改变显示记录单位 |
| v | 验证分区表 |
| w | 保存退出 |
| x | 附加功能（仅专家） |
[root@localhost ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x4aac79af.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): m
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition's system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)
Command (m for help): p
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x4aac79af
Device Boot Start End Blocks Id System
Command (m for help):
如下，我们决定采取如下分区策略要求：
a、一个主分区，2G空间；
b、 一个扩展分区，剩余所有空间；
c、在扩展分区中，分配第一个逻辑分区，分2G空间；
分区步骤如下所示：
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition's system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)
#查看当前分区状态
Command (m for help): p
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x4aac79af
Device Boot Start End Blocks Id System
#查看当前分区号列表
Command (m for help): l
0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris
1 FAT12 39 Plan 9 82 Linux swap / So c1 DRDOS/sec (FAT-
2 XENIX root 3c PartitionMagic 83 Linux c4 DRDOS/sec (FAT-
3 XENIX usr 40 Venix 80286 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
4 FAT16 <32M 41 PPC PReP Boot 85 Linux extended c7 Syrinx
5 Extended 42 SFS 86 NTFS volume set da Non-FS data
6 FAT16 4d QNX4.x 87 NTFS volume set db CP/M / CTOS / .
7 HPFS/NTFS 4e QNX4.x 2nd part 88 Linux plaintext de Dell Utility
8 AIX 4f QNX4.x 3rd part 8e Linux LVM df BootIt
9 AIX bootable 50 OnTrack DM 93 Amoeba e1 DOS access
a OS/2 Boot Manag 51 OnTrack DM6 Aux 94 Amoeba BBT e3 DOS R/O
b W95 FAT32 52 CP/M 9f BSD/OS e4 SpeedStor
c W95 FAT32 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs
e W95 FAT16 (LBA) 54 OnTrackDM6 a5 FreeBSD ee GPT
f W95 Ext'd (LBA) 55 EZ-Drive a6 OpenBSD ef EFI (FAT-12/16/
10 OPUS 56 Golden Bow a7 NeXTSTEP f0 Linux/PA-RISC b
11 Hidden FAT12 5c Priam Edisk a8 Darwin UFS f1 SpeedStor
12 Compaq diagnost 61 SpeedStor a9 NetBSD f4 SpeedStor
14 Hidden FAT16 <3 63 GNU HURD or Sys ab Darwin boot f2 DOS secondary
16 Hidden FAT16 64 Novell Netware af HFS / HFS+ fb VMware VMFS
17 Hidden HPFS/NTF 65 Novell Netware b7 BSDI fs fc VMware VMKCORE
18 AST SmartSleep 70 DiskSecure Mult b8 BSDI swap fd Linux raid auto
1b Hidden W95 FAT3 75 PC/IX bb Boot Wizard hid fe LANstep
1c Hidden W95 FAT3 80 Old Minix be Solaris boot ff BBT
1e Hidden W95 FAT1
#创建一个分区类型
Command (m for help): n
#提示选择分区类型：主分区还是扩展分区
Command action
e extended
p primary partition (1-4)
#根据提示输入p，表示创建一个主分区
p
#该主分区的编号，建议按照顺序来
Partition number (1-4): 1
#表示把该硬盘分成1到1305块，从哪一个数据块开始，默认从1开始，此处建议从1开始
First cylinder (1-1305, default 1):
#提示表示第一个主分区建立完成
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-1305, default 1305): +2G
#继续输命令，此处继续创建一个分区
Command (m for help): n
Command action
e extended
p primary partition (1-4)
#根据提示，选择创建一个扩展分区
e
#因为主分区和扩展分区一共四个，已经创建了一个主分区，此处就依次序，选2
Partition number (1-4): 2
#表示目前扩展分区的可选空间从263开始，默认为263，选择默认（不建议断开设置）
First cylinder (263-1305, default 263):
#提示表示一个扩展分区创建完成
Using default value 263
Last cylinder, +cylinders or +size{K,M,G} (263-1305, default 1305):
Using default value 1305
#查询下当前分区状态
Command (m for help): p
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x4aac79af
Device Boot Start End Blocks Id System
/dev/sdb1 1 262 2104483+ 83 Linux
/dev/sdb2 263 1305 8377897+ 5 Extended
#如上，符合我们的创建目标
#在此，在扩展分区中，试着创建一个逻辑分区（因为扩展分区内无法写人文件，但可以在#扩展分区中创建逻辑分区来实现分区写入数据的目的）
Command (m for help): n
#提示要创建一个逻辑分区还是主分区
Command action
l logical (5 or over)
p primary partition (1-4)
#选择l表示要创建一个逻辑分区
l
#如下，同上，选择默认
First cylinder (263-1305, default 263):
#提示逻辑分区创建完成
Using default value 263
Last cylinder, +cylinders or +size{K,M,G} (263-1305, default 1305): +2G
#查询当前磁盘分区状况
Command (m for help): p
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x4aac79af
Device Boot Start End Blocks Id System
/dev/sdb1 1 262 2104483+ 83 Linux
/dev/sdb2 263 1305 8377897+ 5 Extended
/dev/sdb5 263 524 2104483+ 83 Linux
#注意，只有保存，更改才有效果
Command (m for help): w
#如下提示表示修改并保存退出
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@localhost ~]#
4、重新读取分区表信息
[root@localhost ~] # partprobe
[root@localhost ~]# partprobe
Warning: WARNING: the kernel failed to re-read the partition table on /dev/sda (设备或资源忙). As a result, it may not reflect all of your changes until after reboot.
Warning: 无法以读写方式打开 /dev/sr0 (只读文件系统)。/dev/sr0 已按照只读方式打开。
Warning: 无法以读写方式打开 /dev/sr0 (只读文件系统)。/dev/sr0 已按照只读方式打开。
Error: 无法让分区超出磁盘！
[root@localhost ~]#
注意：如果上方保存退出时，正常，表示一切成功，如果出现错误，因为分区表被占用（比如分区完成，保存了两次），提示要重启系统，这时，可以通过该命令，代替重启系统。如上虽然有警告，但属于正常提示，分区正常完成，只是光盘等不存在。
5、格式化分区
[root@localhost ~ ]# mkfs -t ext4 /dev/sdb1
示例：
在完成上方后，通过fdisk -l 命令查询下当前分区格式化
[root@localhost ~]# fdisk -l
Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000e9453
Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 64 2611 20458496 8e Linux LVM
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x4aac79af
Device Boot Start End Blocks Id System
/dev/sdb1 1 262 2104483+ 83 Linux
/dev/sdb2 263 1305 8377897+ 5 Extended
/dev/sdb5 263 524 2104483+ 83 Linux
Disk /dev/mapper/VolGroup-lv_root: 18.8 GB, 18798870528 bytes
255 heads, 63 sectors/track, 2285 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/VolGroup-lv_swap: 2147 MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
[root@localhost ~]#
注意如上，sdb2 是扩展分区，不能格式化，也不能写入数据！！！
现在格式化sdb1 和sdb5
[root@localhost ~]# mkfs -t ext4 /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
文件系统标签=
操作系统:Linux
块大小=4096 (log=2)
分块大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
131648 inodes, 526120 blocks
26306 blocks (5.00%) reserved for the super user
第一个数据块=0
Maximum filesystem blocks=541065216
17 block groups
32768 blocks per group, 32768 fragments per group
7744 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
正在写入inode表: 完成
Creating journal (16384 blocks): 完成
Writing superblocks and filesystem accounting information: 完成
This filesystem will be automatically checked every 32 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@localhost ~]# mkfs -t ext4 /dev/sdb5
mke2fs 1.41.12 (17-May-2010)
文件系统标签=
操作系统:Linux
块大小=4096 (log=2)
分块大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
131648 inodes, 526120 blocks
26306 blocks (5.00%) reserved for the super user
第一个数据块=0
Maximum filesystem blocks=541065216
17 block groups
32768 blocks per group, 32768 fragments per group
7744 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
正在写入inode表: 完成
Creating journal (16384 blocks): 完成
Writing superblocks and filesystem accounting information: 完成
This filesystem will be automatically checked every 34 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@localhost ~]#
如上，没有报错，表示格式化完成
6、建立挂载点并挂载
[root@localhost ~]#mkdir /disk1
[root@localhost ~]#mount /dev/sdb1 /disk1/
[root@localhost ~]# mkdir /disk1
[root@localhost ~]# mkdir /disk5
[root@localhost ~]# mount /dev/sdb1 /disk1
[root@localhost ~]# mount /dev/sdb5 /disk5
[root@localhost ~]# mount
/dev/mapper/VolGroup-lv_root on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw,rootcontext="system_u:object_r:tmpfs_t:s0")
/dev/sda1 on /boot type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
gvfs-fuse-daemon on /root/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev)
/dev/sr0 on /media/Ubuntu 14.04.5 LTS amd64 type iso9660 (ro,nosuid,nodev,uhelper=udisks,uid=0,gid=0,iocharset=utf8,mode=0400,dmode=0500)
/dev/sdb1 on /disk1 type ext4 (rw)
/dev/sdb5 on /disk5 type ext4 (rw)
[root@localhost ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/VolGroup-lv_root
17938864 8059304 8961648 48% /
tmpfs 953092 76 953016 1% /dev/shm
/dev/sda1 487652 41364 420688 9% /boot
/dev/sr0 1078176 1078176 0 100% /media/Ubuntu 14.04.5 LTS amd64
/dev/sdb1 2005848 3096 1897528 1% /disk1
/dev/sdb5 2005848 3096 1897528 1% /disk5
如上，挂载完成并通过检查
但是，注意如上方法，只能临时生效，每次重启系统需要重新挂载，那如何长久生效呢？
二、fdisk分区——自动挂载与fstab文件修复
1、自动挂载（一般比如硬盘、boot mnt分区等等）：
实质就是在/etc/fstab文件中完成自动挂载配置：
》第一字段：分区设备文件名或UUID（硬盘通用唯一识别码）
》第二字段：挂载点
》第三字段：文件系统名称
》第四字段：挂载参数
》第五字段：指定分区是否被dump备份，0代表不备份，1代表每天备份，2代表不定期备份，备份就是分区自动备份内容到lost-found 文件；
》第六字段：指定分区是否被fsck检测，0代表不检测，其他数字代表检测的优先级，那么当然1的优先级比2高，系统会先检测根目录，个人创建的分区，
一般应该为2
注意：该文件一旦出错，系统可能无法启动，则需要fsck自动修复
[root@localhost ~]# vim /etc/fstab
#
# /etc/fstab
# Created by anaconda on Sun Nov 25 22:51:34 2018
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/VolGroup-lv_root / ext4 defaults 1 1
UUID=ae089b3b-ead9-401d-b17f-80d4575f207f /boot ext4 defaults 1 2
/dev/mapper/VolGroup-lv_swap swap swap defaults 0 0
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
~
~
~
~
"/etc/fstab" 15L, 779C 1,0-1）如何查看分区的UUID？
使用如下命令查看：
[root@localhost ~]# dumpe2fs -h 设备文件名 (-h表示只查看超级块儿信息)
示例：如下，里面会有UUID选项和值
[root@localhost ~]# dumpe2fs -h /dev/sdb1
dumpe2fs 1.41.12 (17-May-2010)
Filesystem volume name: <none>
Last mounted on: <not available>
Filesystem UUID: 042f7bd6-d557-4137-b881-02b0b0cb14d6
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem flags: signed_directory_hash
Default mount options: (none)
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 131648
Block count: 526120
Reserved block count: 26306
Free blocks: 500688
Free inodes: 131637
First block: 0
Block size: 4096
Fragment size: 4096
Reserved GDT blocks: 128
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 7744
Inode blocks per group: 484
Flex block group size: 16
Filesystem created: Mon Dec 10 08:02:59 2018
Last mount time: Mon Dec 10 08:08:40 2018
Last write time: Mon Dec 10 08:08:40 2018
Mount count: 1
Maximum mount count: 32
Last checked: Mon Dec 10 08:02:59 2018
Check interval: 15552000 (6 months)
Next check after: Sat Jun 8 08:02:59 2019
Lifetime writes: 97 MB
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 256
Required extra isize: 28
Desired extra isize: 28
Journal inode: 8
Default directory hash: half_md4
Directory Hash Seed: 9f7752db-881a-4005-9985-1cf59fd4c88b
Journal backup: inode blocks
Journal features: (none)
日志大小: 64M
Journal length: 16384
Journal sequence: 0x00000001
Journal start: 0
[root@localhost ~]#
2、分区自动挂载
[root@localhost ~] #vi /etc/fstab
省略部分输出
/dev/sdb1 /disk1 ext4 defaults 1 2
写这个文件时特别注意，千万别写错
所以，不要先重启，应该先测试是否有问题，方法：
mount -a
如果回车无错误提示，表示修改正确
[root@localhost ~]# mount -a
[root@localhost ~]#
如上，表示正确故意出错修改示例：
1 2
/dev/mapper/VolGroup-lv_swap swap swap defaults 0 0
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
/dev/sdb /disk1 ext4 defaults 1 2
/dev/sdb5 /disk5 ext4 defaults 1 2
~ 如上，故意将disk1对应的设备文件名写错，然后保存
之后重启虚拟机，可以通过命令 reboot，查看虚拟机
提示输入root密码，根据提示进入，发现无法修改，但有提示错误在哪一行
3、/etc/fstab 文件修复
根据如上提示，我们可以通过如下方式进行
重新挂载根分区，赋予读写权限
[root@localhost ~] mount -o remount.rw /
然后再vim /etc/fstab 命令打开，修改正确，然后保存退出
再reboot命令验证，应该是正确的。
但特别注意：该修复不是万能的，如果连根分区都错了，无法挂载根分区，无法出现
如上错误提示信息，就真的崩溃了，所以，修改该文件特别要小心！！！！！！！！！！！！！！！！！