Difference between revisions of "Fdisk (简体中文)"

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{{Related|Partitioning (简体中文)}}
 
{{Related|Partitioning (简体中文)}}
 
{{Related articles end}}
 
{{Related articles end}}
{{TranslationStatus (简体中文)|Fdisk|2018-08-31|537498}}
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{{TranslationStatus (简体中文)|Fdisk|2018-08-31|538937}}
  
 
[https://git.kernel.org/cgit/utils/util-linux/util-linux.git/ util-linux fdisk] 是基于命令行界面的分区表创建和编辑工具。一个硬盘需要分为一个或多个分区,这个信息在分区表里面记录。
 
[https://git.kernel.org/cgit/utils/util-linux/util-linux.git/ util-linux fdisk] 是基于命令行界面的分区表创建和编辑工具。一个硬盘需要分为一个或多个分区,这个信息在分区表里面记录。
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=== Using dd ===
 
=== Using dd ===
  
{{Move|Disk cloning#Using dd|''dd'' is not part of {{Pkg|util-linux}} and does not have anything to do with ''fdisk''.}}
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See [[Dd#Backup and restore MBR partition table]].
 
 
The MBR is stored in the the first 512 bytes of the disk. It consists of 4 parts:
 
 
 
# The first 440 bytes contain the bootstrap code (boot loader).
 
# The next 6 bytes contain the disk signature.
 
# The next 64 bytes contain the partition table (4 entries of 16 bytes each, one entry for each primary partition).
 
# The last 2 bytes contain a boot signature.
 
 
 
To save the MBR as {{ic|mbr_file.img}}:
 
 
 
# dd if=/dev/sd''X'' of=''/path/to/mbr_file.img'' bs=512 count=1
 
 
 
You can also extract the MBR from a full dd disk image:
 
 
 
# dd if=''/path/to/disk.img'' of=''/path/to/mbr_file.img'' bs=512 count=1
 
 
 
To restore (be careful, this destroys the existing partition table and with it access to all data on the disk):
 
 
 
# dd if=/''path/to/mbr_file.img'' of=/dev/sd''X'' bs=512 count=1
 
 
 
{{Warning|Restoring the MBR with a mismatching partition table will make your data unreadable and nearly impossible to recover. If you simply need to reinstall the bootloader see their respective pages as they also employ the [http://www.pixelbeat.org/docs/disk/ DOS compatibility region]: [[GRUB]] or [[Syslinux]].}}
 
 
 
If you only want to restore the boot loader, but not the primary partition table entries, just restore the first 440 bytes of the MBR:
 
 
 
# dd if=''/path/to/mbr_file.img'' of=/dev/sd''X'' bs=440 count=1
 
 
 
To restore only the partition table, one must use:
 
 
 
# dd if=''/path/to/mbr_file.img'' of=/dev/sd''X'' bs=1 skip=446 count=64
 
 
 
To erase the MBR bootstrap code (may be useful if you have to do a full reinstall of another operating system) only the first 440 bytes need to be zeroed:
 
 
 
# dd if=/dev/zero of=/dev/sd''X'' bs=440 count=1
 
  
 
=== Using sfdisk ===
 
=== Using sfdisk ===

Revision as of 09:16, 31 August 2018

翻译状态: 本文是英文页面 Fdisk翻译,最后翻译时间:2018-08-31,点击这里可以查看翻译后英文页面的改动。

util-linux fdisk 是基于命令行界面的分区表创建和编辑工具。一个硬盘需要分为一个或多个分区,这个信息在分区表里面记录。

本文介绍 fdisk(8)sfdisk(8) 工具的使用。

Tip: cfdisk(8) 工具提供了基本的功能和文本界面。

安装

要使用 fdisk 及相关工具,请使用 util-linux 软件包,这个软件包已经位于 base 软件包组。

显示分区

To list partition tables and partitions on a device, you can run the following, where device is a name like /dev/sda:

# fdisk -l /dev/sda
Note: If the device is not specified, fdisk will list all partitions in /proc/partitions.

备份和恢复分区

Before making changes to a hard disk, you may want to backup the partition table and partition scheme of the drive. You can also use a backup to copy the same partition layout to numerous drives.

Using dd

See Dd#Backup and restore MBR partition table.

Using sfdisk

For both GPT and MBR you can use sfdisk to save the partition layout of your device to a file with the -d/--dump option. Run the following command for device /dev/sda:

# sfdisk -d /dev/sda > sda.dump

The file should look something like this for a single ext4 partition that is 1 GiB in size:

sda.dump
label: gpt
label-id: AAAAAAAA-BBBB-CCCC-DDDD-EEEEEEEEEEEE
device: /dev/sda
unit: sectors
first-lba: 34
last-lba: 1048576

/dev/sda1 : start=2048, size=1048576, type=0FC63DAF-8483-4772-8E79-3D69D8477DE4, uuid=BBF1CD36-9262-463E-A4FB-81E32C12BDE7

To later restore this layout you can run:

# sfdisk /dev/sda < sda.dump

创建分区表和分区

The first step to partitioning a disk is making a partition table. After that, the actual partitions are created according to the desired partition scheme. See the partition table article to help decide whether to use MBR or GPT.

Before beginning, you may wish to backup your current partition table and scheme.

Recent versions of fdisk have abandoned the deprecated system of using cylinders as the default display unit, as well as MS-DOS compatibility by default. fdisk automatically aligns all partitions to 2048 sectors, or 1 MiB, which should work for all EBS sizes that are known to be used by SSD manufacturers. This means that the default settings will give you proper alignment.

Start fdisk against your drive as root. In this example we are using /dev/sda:

# fdisk /dev/sda

This opens the fdisk dialogue where you can type in commands.

Create new table

Warning: If you create a new partition table on a disk with data on it, it will erase all the data on the disk. Make sure this is what you want to do.

To create a new partition table and clear all current partition data type o at the prompt for a MBR partition table or g for a GUID Partition Table (GPT). Skip this step if the table you require has already been created.

Create partitions

Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: Place each step into a subsection. (Discuss in Talk:Fdisk (简体中文)#)

Create a new partition with the n command. You enter a partition type, partition number, starting sector, and an ending sector.

When prompted, specify the partition type, type p to create a primary partition or e to create an extended one. There may be up to four primary partitions.

The first sector must be specified in absolute terms using sector numbers. The last sector can be specified using the absolute position in sectors or using the + symbol to specify a position relative to the start sector measured in sectors, kibibytes (K), mebibytes (M), gibibytes (G), tebibytes (T), or pebibytes (P); for instance, setting +2G as the last sector will specify a point 2GiB after the start sector. Pressing the Enter key with no input specifies the default value, which is the start of the largest available block for the start sector and the end of the same block for the end sector.

Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: Suggest using Discoverable Partitions. (Discuss in Talk:Fdisk (简体中文)#)

Select the partition's type id. The default, Linux filesystem, should be fine for most use. Press l to show the codes list. You can make the partition bootable by typing a.

Tip:
  • When partitioning it is always a good idea to follow the default values for first and last partition sectors. Additionally, specify partition sizes with the +<size>{M,G,...} notation. Such partitions are always aligned according to the device properties.
  • On a MBR partitioned disk leave at least 16.5 KiB free space at the end of the disk to simplify converting between MBR and GPT if the need ever arises.
  • EFI system partition requires type EFI System.
  • GRUB requires a BIOS boot partition with type BIOS boot when installing GRUB to a disk.
  • It is recommended to use Linux swap for any swap partitions, since systemd will automount it.

See the respective articles for considerations concerning the size and location of these partitions.

Repeat this procedure until you have the partitions you desire.

Write changes to disk

Write the table to disk and exit via the w command.

Tips and tricks

Sort partitions

This applies for when a new partition is created in the space between two partitions or a partition is deleted. /dev/sda is used in this example.

# sfdisk -r /dev/sda

After sorting the partitions if you are not using Persistent block device naming, it might be required to adjust the /etc/fstab and/or the /etc/crypttab configuration files.

Note: The kernel must read the new partition table for the partitions (e.g. /dev/sda1) to be usable. Reboot the system or tell the kernel to reread the partition table.

See also