Linux磁盘分区

1、添加10G的硬盘。 实际上在服务器上支持热插拔

2、fdisk -l查看   

[root@linux-xl ~]# fdisk -l   #如果识别不到新插的硬盘，查看磁盘，虚拟机正常需要重启才能加载新的磁盘。

 

Disk /dev/sda: 53.7 GB, 53687091200 bytes, 104857600 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk label type: dos

Disk identifier: 0x000cd7c5

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *        2048     2099199     1048576   83  Linux

/dev/sda2         2099200    94373887    46137344   83  Linux

/dev/sda3        94373888   102502399     4064256   82  Linux swap / Solaris

/dev/sda4       102502400   104857599     1177600    5  Extended

/dev/sda5       102504448   104601599     1048576   83  Linux

 

Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors  #这里的sdb为新加的磁盘

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

 

3、对于磁盘可以不分区，直接格式化一整块使用；但通常都是先分区，后格式化。

fdisk是mbr分区模式，最高只支持2TB，最多只有主分区primary加上扩展分区extended为4，想要多个分区需要第四个分区为扩展分区extended，并在扩展分区里面分多个逻辑分区。 扩展分区仅仅只是一个外壳不支持格式化，真正存储的是逻辑分区。

[root@linux-xl ~]# fdisk /dev/sdb

Welcome to fdisk (util-linux 2.23.2).

 

Changes will remain in memory only, until you decide to write them.

Be careful before using the write command.

 

Device does not contain a recognized partition table

Building a new DOS disklabel with disk identifier 0x189fc246.

 

Command (m for help): n   #创建一个新的分区(这里通常使用的是 n：创建一个新的分区；p：罗列出分区；w：保存并退出；d：删除一个分区；q：不保存直接退出)

Partition type:

   p   primary (0 primary, 0 extended, 4 free)     #主分区：如果想都用分区，最多只能划分四个

   e   extended                                          #扩展分区：包含逻辑分区

Select (default p): p   

Partition number (1-4, default 1): 1

First sector (2048-20971519, default 2048):     #这里起始扇区都使用默认，直接回车即可。

Using default value 2048

Last sector, +sectors or +size{K,M,G} (2048-20971519, default 20971519):+2G      #划分2个G的空间。

Partition 1 of type Linux and of size 2 GiB is set

Command (m for help): p  #列出分区

 

Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk label type: dos

Disk identifier: 0x189fc246

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1            2048     4196351     2097152   83  Linux           # 此时可以看到刚划分的分区

Command (m for help): n      #主分区分完过后，再新建分区就不会提示了

Partition type:

   p   primary (1 primary, 0 extended, 3 free)

   e   extended

Select (default p):        #默认回车

Using default response p

Partition number (2-4, default 2):    #默认回车

First sector (4196352-20971519, default 4196352):   #默认回车

Using default value 4196352

Last sector, +sectors or +size{K,M,G} (4196352-20971519, default 20971519): +2G   #新建2G的主分区

Partition 2 of type Linux and of size 2 GiB is set

Command (m for help): p    #列出分区

 

Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk label type: dos

Disk identifier: 0x189fc246

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1            2048     4196351     2097152   83  Linux

/dev/sdb2         4196352     8390655     2097152   83  Linux

Command (m for help): n    #新建一个分区

Partition type:

   p   primary (2 primary, 0 extended, 2 free)

   e   extended

Select (default p):        #回车默认主分区

Using default response p

Partition number (3,4, default 3):    #默认回车从3开始

First sector (8390656-20971519, default 8390656):   #默认回车

Using default value 8390656

Last sector, +sectors or +size{K,M,G} (8390656-20971519, default 20971519): +1G  #划分1个G的主分区

Partition 3 of type Linux and of size 1 GiB is set

Command (m for help): p    #列出分区

 

Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk label type: dos

Disk identifier: 0x189fc246

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1            2048     4196351     2097152   83  Linux

/dev/sdb2         4196352     8390655     2097152   83  Linux

/dev/sdb3         8390656    10487807     1048576   83  Linux

 

Command (m for help): n   #新建分区

Partition type:

   p   primary (3 primary, 0 extended, 1 free)

   e   extended

Select (default e): e    #划分扩展分区

Selected partition 4

First sector (10487808-20971519, default 10487808):   #默认回车

Using default value 10487808

Last sector, +sectors or +size{K,M,G} (10487808-20971519, default 20971519):   #默认回车划分剩余空间给扩展分区

Using default value 20971519

Partition 4 of type Extended and of size 5 GiB is set

Command (m for help): p   #列出分区

 

Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk label type: dos

Disk identifier: 0x189fc246

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1            2048     4196351     2097152   83  Linux

/dev/sdb2         4196352     8390655     2097152   83  Linux

/dev/sdb3         8390656    10487807     1048576   83  Linux

/dev/sdb4        10487808    20971519     5241856    5  Extended

Command (m for help): n   #可以看到提示变了，只能是划分逻辑分区了。

All primary partitions are in use

Adding logical partition 5

First sector (10489856-20971519, default 10489856):

Using default value 10489856

Last sector, +sectors or +size{K,M,G} (10489856-20971519, default 20971519): +1G  #划分1G大小的逻辑分区

Partition 5 of type Linux and of size 1 GiB is set

Command (m for help): p   #列出分区

 

Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk label type: dos

Disk identifier: 0x189fc246

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1            2048     4196351     2097152   83  Linux

/dev/sdb2         4196352     8390655     2097152   83  Linux

/dev/sdb3         8390656    10487807     1048576   83  Linux

/dev/sdb4        10487808    20971519     5241856    5  Extended

/dev/sdb5        10489856    12587007     1048576   83  Linux

Command (m for help): n   #再划分一个逻辑分区

All primary partitions are in use

Adding logical partition 6

First sector (12589056-20971519, default 12589056):

Using default value 12589056

Last sector, +sectors or +size{K,M,G} (12589056-20971519, default 20971519): +1G   #划分1G大小的逻辑分区

Partition 6 of type Linux and of size 1 GiB is set

 

Command (m for help): p  #列出分区

 

Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk label type: dos

Disk identifier: 0x189fc246

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1            2048     4196351     2097152   83  Linux

/dev/sdb2         4196352     8390655     2097152   83  Linux

/dev/sdb3         8390656    10487807     1048576   83  Linux

/dev/sdb4        10487808    20971519     5241856    5  Extended

/dev/sdb5        10489856    12587007     1048576   83  Linux

/dev/sdb6        12589056    14686207     1048576   83  Linux

Command (m for help): d   #删掉一个分区6

Partition number (1-6, default 6): 6    #回车默认是6

Partition 6 is deleted

 

Command (m for help): p  #列出分区

 

Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk label type: dos

Disk identifier: 0x189fc246

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1            2048     4196351     2097152   83  Linux

/dev/sdb2         4196352     8390655     2097152   83  Linux

/dev/sdb3         8390656    10487807     1048576   83  Linux

/dev/sdb4        10487808    20971519     5241856    5  Extended

/dev/sdb5        10489856    12587007     1048576   83  Linux

Command (m for help): w  #保存并退出

The partition table has been altered!

 

Calling ioctl() to re-read partition table.

Syncing disks.

查看刚划分出来的分区，此时已经成功划分。下一步就是格式化了。

[root@linux-xl ~]# fdisk -l /dev/sdb   

 

Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk label type: dos

Disk identifier: 0x189fc246

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1            2048     4196351     2097152   83  Linux

/dev/sdb2         4196352     8390655     2097152   83  Linux

/dev/sdb3         8390656    10487807     1048576   83  Linux

/dev/sdb4        10487808    20971519     5241856    5  Extended

/dev/sdb5        10489856    12587007     1048576   83  Linux

当我们在创建磁盘分区的时候，有三种分区可选，扩展分区（e），主分区（p），逻辑分区（l）。

我们最多只能创建4个分区（4个中不包括逻辑分区），如果想创建多个分区，可以是3个主分区和1个扩展分区组合。然后在扩展分区中，创建逻辑分区（可以创建无限个逻辑分区）； 需要注意的是，扩展分区相当于一个空壳子，是不可以格式化的（不可以使用），只有它的子分区才可以格式化。在fdisk中划分分区的时候，使用d选项可以删除你想要删除的那个分区，需要注意的是，当扩展分区中有子分区（逻辑分区）的时候，删除扩展分区会连同子分区一起删除。