linux命令之磁盘与文件系统管理命令（上）

1.fdisk：磁盘分区工具

该命令是linux下常用的磁盘分区工具，但是只能给小于2TB的磁盘划分分区。

常用参数为-l，显示所有磁盘分区的信息。

示例：

1）显示磁盘分区列表

[root@boxiaoyuan ~]# fdisk -l  # 查看当前系统的所有磁盘分区信息
Disk /dev/sda: 21.5 GB,  bytes  # 磁盘/dev/sda的大小
 heads,  sectors/track,  cylinders  # 255个虚拟磁头，63个扇区/磁道，2610个柱面
Units = cylinders of  *  =  bytes  # 一个柱面的大小为8225280bytes
Sector size (logical/physical):  bytes /  bytes  #每个扇区的字节数
I/O size (minimum/optimal):  bytes /  bytes  # 每次读写的字节数
Disk identifier: 0x0000db9b

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1                                 Linux swap / Solaris
/dev/sda2   *                         Linux

说明：Device表示分区；Boot表示启动分区，用*表示；Start表示开始的柱面；End表示结束的柱面；Blocks表示快数量；Id表示分区类型Id；System表示分区类型。

2）模拟分区实战

[root@boxiaoyuan ~]# fdisk /dev/sdb  # 不加参数，直接接设备名就可以进行分区
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x784b7b62.
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  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): n
Command action
   e   extended
   p   primary partition (-)
p
Partition number (-):
First cylinder (-, default ):
Using default value 
Last cylinder, +cylinders or +size{K,M,G} (-, default ): +100M

Command (m for help): p

Disk /dev/sdb:  MB,  bytes
 heads,  sectors/track,  cylinders
Units = cylinders of  *  =  bytes
Sector size (logical/physical):  bytes /  bytes
I/O size (minimum/optimal):  bytes /  bytes
Disk identifier: 0x784b7b62

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1                               +    Linux

Command (m for help): n
Command action
   e   extended
   p   primary partition (-)
e
Partition number (-):
First cylinder (-, default ):
Using default value 
Last cylinder, +cylinders or +size{K,M,G} (-, default ):
Using default value 

Command (m for help): p

Disk /dev/sdb:  MB,  bytes
 heads,  sectors/track,  cylinders
Units = cylinders of  *  =  bytes
Sector size (logical/physical):  bytes /  bytes
I/O size (minimum/optimal):  bytes /  bytes
Disk identifier: 0x784b7b62

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1                               +    Linux
/dev/sdb2                                   Extended

Command (m for help): n
Command action
   l   logical ( or over)
   p   primary partition (-)
p
Partition number (-): 
No free sectors available

Command (m for help): n
Command action
   l   logical ( or over)
   p   primary partition (-)
l
First cylinder (-, default ):
Using default value 
Last cylinder, +cylinders or +size{K,M,G} (-, default ): +400M

Command (m for help): p

Disk /dev/sdb:  MB,  bytes
 heads,  sectors/track,  cylinders
Units = cylinders of  *  =  bytes
Sector size (logical/physical):  bytes /  bytes
I/O size (minimum/optimal):  bytes /  bytes
Disk identifier: 0x784b7b62

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1                               +    Linux
/dev/sdb2                                   Extended
/dev/sdb5                              +    Linux

Command (m for help): n
Command action
   l   logical ( or over)
   p   primary partition (-)
l
First cylinder (-, default ):
Using default value 
Last cylinder, +cylinders or +size{K,M,G} (-, default ):
Using default value 

Command (m for help): p

Disk /dev/sdb:  MB,  bytes
 heads,  sectors/track,  cylinders
Units = cylinders of  *  =  bytes
Sector size (logical/physical):  bytes /  bytes
I/O size (minimum/optimal):  bytes /  bytes
Disk identifier: 0x784b7b62

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1                               +    Linux
/dev/sdb2                                   Extended
/dev/sdb5                              +    Linux
/dev/sdb6                             +    Linux

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
[root@boxiaoyuan ~]# partprobe /dev/sdb  # 执行该命令通知内核分区表已更新，不需要重启系统就可以让分区生效

格式化磁盘

[root@boxiaoyuan ~]# mkfs.ext4 /dev/sdb1
mke2fs 1.41. (-May-)
文件系统标签=
操作系统:Linux
块大小= (log=)
分块大小= (log=)
Stride= blocks, Stripe width= blocks
 inodes,  blocks
 blocks (5.00%) reserved for the super user
第一个数据块=
Maximum filesystem blocks=
 block groups
 blocks per group,  fragments per group
 inodes per group
Superblock backups stored on blocks:
        , , , , 

正在写入inode表: 完成
Creating journal ( blocks): 完成
Writing superblocks and filesystem accounting information: 完成

This filesystem will be automatically checked every  mounts or
 days, whichever comes first.  Use tune2fs -c or -i to override.

挂载磁盘

[root@boxiaoyuan ~]# mount /dev/sdb1 /mnt
[root@boxiaoyuan ~]# df -T
Filesystem     Type    1K-blocks    Used Available Use% Mounted on
/dev/sda2      ext4           % /
tmpfs          tmpfs                   % /dev/shm
/dev/sr0       iso9660              % /media/CentOS_6.8_Final
/dev/sdb1      ext4                   % /mnt

2.partprobe：更新内核的硬盘分区表信息

该命令用于在硬盘分区发生变化时，更新内核的硬盘分区表数据，可以在不重启系统时就更新分区表信息。

[root@boxiaoyuan ~]# partprobe /dev/sdb

3.parted：磁盘分区工具

该命令用于对大于2TB的磁盘进行分区，并且要将磁盘转换为GPT格式。

常用的参数选项为-l，显示所有磁盘分区的信息。

通过parted -h或者直接通过parted进入交互模式后通过-h查看帮助。

[root@boxiaoyuan ~]# parted
GNU Parted 2.1
使用 /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) h
  align-check TYPE N
  check NUMBER
  cp [FROM-DEVICE] FROM-NUMBER TO-NUMBER
  help [COMMAND]
  mklabel,mktable LABEL-TYPE    # 创建分区表
  mkfs NUMBER FS-TYPE
  mkpart PART-TYPE [FS-TYPE] START END  # 创建分区
  mkpartfs PART-TYPE FS-TYPE START END  # 创建带有文件系统的分区
  move NUMBER START END
  name NUMBER NAME
  print [devices|free|list,all|NUMBER]    # 显示分区表信息
  quit
  rescue START END
  resize NUMBER START END
  rm NUMBER  # 删除编号NUMBER的分区
  select DEVICE
  set NUMBER FLAG STATE
  toggle [NUMBER [FLAG]]
  unit UNIT
  version
(parted) 

示例：

1）显示分区情况

[root@boxiaoyuan ~]# parted -l
Model: VMware, VMware Virtual S (scsi)  # 磁盘类型
Disk /dev/sda: .5GB  # 磁盘大小
Sector size (logical/physical): 512B/512B  # 扇区大小
Partition Table: msdos  # 分区表类型

Number  Start   End     Size    Type     File system     标志
       1049kB  8591MB  8590MB  primary  linux-swap(v1)
       8591MB  .5GB  .9GB  primary  ext4            启动

2）模拟分区实战

[root@boxiaoyuan ~]# parted /dev/sdb  # parted直接接需要分区的设备
GNU Parted 2.1
使用 /dev/sdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) mklabel gpt  # 为sdb磁盘创建GPT分区表，大于2TB的磁盘必须执行这一步
(parted) mkpart primary     # 创建主分区，500M
警告: The resulting partition is not properly aligned for best performance.
忽略/Ignore/放弃/Cancel? Ignore   # 忽略警告
(parted) p  # 显示分区表信息
Model: VMware, VMware Virtual S (scsi)
Disk /dev/sdb: 1074MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End    Size   File system  Name     标志
       .4kB  500MB  500MB               primary

(parted) mkpart logical    # 创建逻辑分区，大小为500MB
(parted) p  # 显示分区表信息
Model: VMware, VMware Virtual S (scsi)
Disk /dev/sdb: 1074MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size   File system  Name     标志
       .4kB  500MB   500MB               primary
       501MB   1000MB  499MB               logical

(parted) quit  # 退出
信息: You may need to update /etc/fstab.                                  

[root@boxiaoyuan ~]# ls /dev/sdb*
/dev/sdb  /dev/sdb1  /dev/sdb2
[root@bixiaoyuan ~]# mkfs.ext4 /dev/sdb1  # 格式化
mke2fs 1.41. (-May-)
文件系统标签=
操作系统:Linux
块大小= (log=)
分块大小= (log=)
Stride= blocks, Stripe width= blocks
 inodes,  blocks
 blocks (5.00%) reserved for the super user
第一个数据块=
Maximum filesystem blocks=
 block groups
 blocks per group,  fragments per group
 inodes per group
Superblock backups stored on blocks:
        , , , , , , , 

正在写入inode表: 完成
Creating journal ( blocks): 完成
Writing superblocks and filesystem accounting information: 完成

This filesystem will be automatically checked every  mounts or
 days, whichever comes first.  Use tune2fs -c or -i to override.
[root@boxiaoyuan ~]# mount /dev/sdb1 /mnt  #挂载

4.mkfs：创建linux文件系统

该命令用于在指定的设备或者分区上创建格式化并创建文件系统。

常用的参数有-t：指定要创建的文件系统类型，也可以直接使用mkfs.ext4创建ext4文件系统。

5.df：报告文件系统磁盘空间的使用情况

该命令用于显示文件系统磁盘空间的使用情况。

参数	说明
-h（常用）	以容易理解的格式显示磁盘的使用情况
-i（常用）	显示文件系统的inode信息
-T（常用）	列出文件系统的类型

示例：

1）显示磁盘的使用情况

[root@boxiaoyuan ~]# df
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/sda2             % /
tmpfs                           % /dev/shm

2）-h选项

[root@boxiaoyuan ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda2        12G  .2G  .0G  % /
tmpfs           931M   72K  931M   % /dev/shm

3）列出文件系统的类型

[root@boxiaoyuan ~]# df -T
Filesystem     Type  1K-blocks    Used Available Use% Mounted on
/dev/sda2      ext4         % /
tmpfs          tmpfs                 % /dev/shm

注：本文内容为《跟老男孩学linux运维 核心系统命令实践》的学习笔记。