Linux學習之 fdisk分割槽
阿新 • • 發佈：2018-12-23
1、新增新硬碟用於練習分割槽
操作注意：
1）先給Linux虛擬機器斷電
2）虛擬機器設定選項，選擇新增硬碟，完成後，重啟，
3）查詢當前配置
[[email protected] ~]# 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，發現新增的硬碟被識別了
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 命令分割槽
注意fdisk互動指令說明
| 命令 | 說明 |
| a | 設定可引導標記 |
| b | 編輯bsd磁碟標籤 |
| c | 設定DOS作業系統相容標記 |
| d | 刪除一個分割槽 |
| l | 顯示已知的檔案系統型別。82為Linux swap分割槽，83為Linux分割槽 |
| m | 顯示幫助選單 |
| n | 新建分割槽 |
| o | 建立空白DOS分割槽表 |
| p | 顯示分割槽列表 |
| q | 不儲存退出 |
| s | 新建空白SUN磁碟標籤 |
| t | 改變一個分割槽的系統ID |
| u | 改變顯示記錄單位 |
| v | 驗證分割槽表 |
| w | 儲存退出 |
| x | 附加功能（僅專家） |
[[email protected] ~]# 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，我們決定採取如下分割槽策略要求：
a、一個主分割槽，2G空間；
b、 一個擴充套件分割槽，剩餘所有空間；
c、在擴充套件分割槽中，分配第一個邏輯分割槽，分2G空間；
分割槽步驟如下所示：
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)
#檢視當前分割槽狀態
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
#檢視當前分割槽號列表
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
#建立一個分割槽型別
Command (m for help): n
#提示選擇分割槽型別：主分割槽還是擴充套件分割槽
Command action
e extended
p primary partition (1-4)
#根據提示輸入p，表示建立一個主分割槽
p
#該主分割槽的編號，建議按照順序來
Partition number (1-4): 1
#表示把該硬碟分成1到1305塊，從哪一個資料塊開始，預設從1開始，此處建議從1開始
First cylinder (1-1305, default 1):
#提示表示第一個主分割槽建立完成
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-1305, default 1305): +2G
#繼續輸命令，此處繼續建立一個分割槽
Command (m for help): n
Command action
e extended
p primary partition (1-4)
#根據提示，選擇建立一個擴充套件分割槽
e
#因為主分割槽和擴充套件分割槽一共四個，已經建立了一個主分割槽，此處就依次序，選2
Partition number (1-4): 2
#表示目前擴充套件分割槽的可選空間從263開始，預設為263，選擇預設（不建議斷開設定）
First cylinder (263-1305, default 263):
#提示表示一個擴充套件分割槽建立完成
Using default value 263
Last cylinder, +cylinders or +size{K,M,G} (263-1305, default 1305):
Using default value 1305
#查詢下當前分割槽狀態
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，符合我們的建立目標
#在此，在擴充套件分割槽中，試著建立一個邏輯分割槽（因為擴充套件分割槽內無法寫人檔案，但可以在#擴充套件分割槽中建立邏輯分割槽來實現分割槽寫入資料的目的）
Command (m for help): n
#提示要建立一個邏輯分割槽還是主分割槽
Command action
l logical (5 or over)
p primary partition (1-4)
#選擇l表示要建立一個邏輯分割槽
l
#如下，同上，選擇預設
First cylinder (263-1305, default 263):
#提示邏輯分割槽建立完成
Using default value 263
Last cylinder, +cylinders or +size{K,M,G} (263-1305, default 1305): +2G
#查詢當前磁碟分割槽狀況
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，只有儲存，更改才有效果
Command (m for help): w
#如下提示表示修改並儲存退出
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[[email protected] ~]#
4、重新讀取分割槽表資訊
[[email protected] ~] # partprobe
[[email protected] ~]# partprobe
Warning: WARNING: the kernel failed to re-read the partition table on /dev/sda (裝置或資源忙). As a result, it may not reflect all of your changes until after reboot.
Warning: 無法以讀寫方式開啟 /dev/sr0 (只讀檔案系統)。/dev/sr0 已按照只讀方式開啟。
Warning: 無法以讀寫方式開啟 /dev/sr0 (只讀檔案系統)。/dev/sr0 已按照只讀方式開啟。
Error: 無法讓分割槽超出磁碟！
[[email protected] ~]#
注意：如果上方儲存退出時，正常，表示一切成功，如果出現錯誤，因為分割槽表被佔用（比如分割槽完成，儲存了兩次），提示要重啟系統，這時，可以通過該命令，代替重啟系統。如上雖然有警告，但屬於正常提示，分割槽正常完成，只是光碟等不存在。
5、格式化分割槽
[[email protected] ~ ]# mkfs -t ext4 /dev/sdb1
示例：
在完成上方後，通過fdisk -l 命令查詢下當前分割槽格式化
[[email protected] ~]# 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
[[email protected] ~]#
注意如上，sdb2 是擴充套件分割槽，不能格式化，也不能寫入資料！！！
現在格式化sdb1 和sdb5
[[email protected] ~]# mkfs -t ext4 /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
檔案系統標籤=
作業系統:Linux
塊大小=4096 (log=2)
分塊大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
131648 inodes, 526120 blocks
26306 blocks (5.00%) reserved for the super user
第一個資料塊=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
正在寫入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.
[[email protected] ~]# mkfs -t ext4 /dev/sdb5
mke2fs 1.41.12 (17-May-2010)
檔案系統標籤=
作業系統:Linux
塊大小=4096 (log=2)
分塊大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
131648 inodes, 526120 blocks
26306 blocks (5.00%) reserved for the super user
第一個資料塊=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
正在寫入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.
[[email protected] ~]#
如上，沒有報錯，表示格式化完成
6、建立掛載點並掛載
[[email protected] ~]#mkdir /disk1
[[email protected] ~]#mount /dev/sdb1 /disk1/
[[email protected] ~]# mkdir /disk1
[[email protected] ~]# mkdir /disk5
[[email protected] ~]# mount /dev/sdb1 /disk1
[[email protected] ~]# mount /dev/sdb5 /disk5
[[email protected] ~]# 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)
[[email protected] ~]# 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，掛載完成並通過檢查
但是，注意如上方法，只能臨時生效，每次重啟系統需要重新掛載，那如何長久生效呢？
二、fdisk分割槽——自動掛載與fstab檔案修復
1、自動掛載（一般比如硬碟、boot mnt分割槽等等）：
實質就是在/etc/fstab檔案中完成自動掛載配置：
》第一欄位：分割槽裝置檔名或UUID（硬碟通用唯一識別碼）
》第二欄位：掛載點
》第三欄位：檔案系統名稱
》第四欄位：掛載引數
》第五欄位：指定分割槽是否被dump備份，0代表不備份，1代表每天備份，2代表不定期備份，備份就是分割槽自動備份內容到lost-found 檔案；
》第六欄位：指定分割槽是否被fsck檢測，0代表不檢測，其他數字代表檢測的優先順序，那麼當然1的優先順序比2高，系統會先檢測根目錄，個人建立的分割槽，
一般應該為2
注意：該檔案一旦出錯，系統可能無法啟動，則需要fsck自動修復
[[email protected] ~]# 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）如何檢視分割槽的UUID？
使用如下命令檢視：
[[email protected] ~]# dumpe2fs -h 裝置檔名 (-h表示只檢視超級塊兒資訊)
示例：如下，裡面會有UUID選項和值
[[email protected] ~]# 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)
日誌大小: 64M
Journal length: 16384
Journal sequence: 0x00000001
Journal start: 0
[[email protected] ~]#
2、分割槽自動掛載
[[email protected] ~] #vi /etc/fstab
省略部分輸出
/dev/sdb1 /disk1 ext4 defaults 1 2
寫這個檔案時特別注意，千萬別寫錯
所以，不要先重啟，應該先測試是否有問題，方法：
mount -a
如果回車無錯誤提示，表示修改正確
[[email protected] ~]# mount -a
[[email protected] ~]#
如上，表示正確故意出錯修改示例：
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，故意將disk1對應的裝置檔名寫錯，然後儲存
之後重啟虛擬機器，可以通過命令 reboot，檢視虛擬機器
提示輸入root密碼，根據提示進入，發現無法修改，但有提示錯誤在哪一行
3、/etc/fstab 檔案修復
根據如上提示，我們可以通過如下方式進行
重新掛載根分割槽，賦予讀寫許可權
[[email protected] ~] mount -o remount.rw /
然後再vim /etc/fstab 命令開啟，修改正確，然後儲存退出
再reboot命令驗證，應該是正確的。
但特別注意：該修復不是萬能的，如果連根分割槽都錯了，無法掛載根分割槽，無法出現
如上錯誤提示資訊，就真的崩潰了，所以，修改該檔案特別要小心！！！！！！！！！！！！！！！！！