Linux 主分区_扩展分区_逻辑分区

1、Linux分区介绍

1.1 分区规定：

　　每个磁盘设备最多4个主分区，或者3个主分区+1个扩展分区，是因为MBR（主引导记录）的分区表（主分区表）只能存放4个分区。

　　扩展分区只能有一个。

　　逻辑分区可以有多个。

　　可以从扩展分区中再次划分多个逻辑分区，逻辑分区编号直接从5开始。

1.2 分区作用：

　　主分区：主要是用来启动操作系统的，它主要放的是操作系统的启动或引导程序，/boot分区最好放在主分区上；

　　扩展分区是不能使用的，它只是做为逻辑分区的容器存在的，先创建一个扩展分区，在扩展分区之上创建逻辑分区；

　　我们真正存放数据的是主分区和逻辑分区，大量数据都放在逻辑分区中。

2、创建主分区

[root@servera ~]# fdisk /dev/vdb

Command (m for help): n　　# 创建新分区
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): p　　# 创建主分区
Partition number (1-4, default 1): 　　# 回车
First sector (2048-10485759, default 2048): 　　# 回车，设置起始扇区
Last sector, +sectors or +size{K,M,G,T,P} (2048-10485759, default 10485759): 409600　　# 设置结尾扇区

Created a new partition 1 of type 'Linux' and of size 199 MiB.

Command (m for help): n
Partition type
   p   primary (1 primary, 0 extended, 3 free)
   e   extended (container for logical partitions)
Select (default p): p　　# 创建主分区
Partition number (2-4, default 2): 　　# 回车
First sector (409601-10485759, default 411648): 　　# 回车，设置起始扇区
Last sector, +sectors or +size{K,M,G,T,P} (411648-10485759, default 10485759): 819200　　# 设置结尾扇区

Created a new partition 2 of type 'Linux' and of size 199 MiB.


Command (m for help): w　　# 保存配置
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

[root@servera ~]# fdisk -l /dev/vdb
Disk /dev/vdb: 5 GiB, 5368709120 bytes, 10485760 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
Disklabel type: dos
Disk identifier: 0x03864530

Device     Boot  Start      End Sectors  Size Id Type
/dev/vdb1         2048   409600  407553  199M 83 Linux
/dev/vdb2       411648   819200  407553  199M 83 Linux

3、创建扩展分区

[root@servera ~]# fdisk /dev/vdb

Command (m for help): n　　# 创建新分区
Partition type
   p   primary (2 primary, 0 extended, 2 free)
   e   extended (container for logical partitions)
Select (default p): e　　# 创建扩展分区
Partition number (3,4, default 3): 　　# 选择分区号
First sector (409601-10485759, default 821248): 　　# 起始扇区
Last sector, +sectors or +size{K,M,G,T,P} (821248-10485759, default 10485759): 　　# 结尾扇区

Created a new partition 3 of type 'Extended' and of size 4.6 GiB.


Command (m for help): w　　# 保存配置
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

[root@servera ~]# fdisk -l /dev/vdb
Disk /dev/vdb: 5 GiB, 5368709120 bytes, 10485760 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
Disklabel type: dos
Disk identifier: 0x03864530

Device     Boot  Start      End Sectors  Size Id Type
/dev/vdb1         2048   409600  407553  199M 83 Linux　　# 主分区
/dev/vdb2       411648   819200  407553  199M 83 Linux　　# 主分区
/dev/vdb3       821248 10485759 9664512  4.6G  5 Extended　　# 扩展分区

4、创建逻辑分区

[root@servera ~]# fdisk /dev/vdb

Command (m for help): n　　# 创建新分区
All space for primary partitions is in use.　　# 提示所有空间都已经分配给主分区使用
Adding logical partition 5　　# 从扩展分区中，自动划分逻辑分区
First sector (823296-10485759, default 823296): 　　# 起始扇区
Last sector, +sectors or +size{K,M,G,T,P} (823296-10485759, default 10485759): 　　# 结尾扇区

Created a new partition 5 of type 'Linux' and of size 4.6 GiB.

Command (m for help): t　　# 分区类型
Partition number (1-3,5, default 5): 
Hex code (type L to list all codes): 8e   # LVM类型

Changed type of partition 'Linux' to 'Linux LVM'.

Command (m for help): w　　# 保存配置
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.


[root@servera ~]# fdisk -l /dev/vdb
Disk /dev/vdb: 5 GiB, 5368709120 bytes, 10485760 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
Disklabel type: dos
Disk identifier: 0x03864530

Device     Boot  Start      End Sectors  Size Id Type
/dev/vdb1         2048   409600  407553  199M 83 Linux
/dev/vdb2       411648   819200  407553  199M 83 Linux
/dev/vdb3       821248 10485759 9664512  4.6G  5 Extended
/dev/vdb5       823296 10485759 9662464  4.6G 8e Linux LVM

[root@servera ~]# mkfs.xfs /dev/vdb5　　# 格式化逻辑分区
meta-data=/dev/vdb5              isize=512    agcount=4, agsize=301952 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=0
         =                       reflink=1
data     =                       bsize=4096   blocks=1207808, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
[root@servera ~]# mount /dev/vdb5 /var/tmp　　# 挂载逻辑分区