磁盘划分

　　管理Linux系统中的硬盘设备最常用的方法就当属是fdisk命令了，这条命令提供了添加、删除、转换分区等等功能于一身的“一站式服务”，不过这条命令的参数是交互式的，而不是像我们以前直接写到命令后面的参数一样，这样在管理硬盘设备的时候特别方便，可以根据需求动态的调整。

 

目的： 将/dev/vdb划分出/u01,/u02,swap三个分区，并设置成开机自动挂载

 

1.划分磁盘

--查看磁盘信息：

[root@app-01 ~]# fdisk -l

Disk /dev/vda: 42.9 GB, 42949672960 bytes
255 heads, 63 sectors/track, 5221 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: 0x0003d038

   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *           1        5222    41940992   83  Linux

Disk /dev/vdb: 536.9 GB, 536870912000 bytes
16 heads, 63 sectors/track, 1040253 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

--划分磁盘/dev/vdb

[root@app-01 ~]# fdisk /dev/vdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x9f199567.
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): n       --建立新分区
Command action
   e   extended
   p   primary partition (1-4)
p　　　　　　　　　　　　　　　　 --选择建立主分区
Partition number (1-4): 1
First cylinder (1-1040253, default 1): 
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-1040253, default 1040253): +300G

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (624154-1040253, default 624154): 
Using default value 624154
Last cylinder, +cylinders or +size{K,M,G} (624154-1040253, default 1040253): +12G

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 3
First cylinder (649121-1040253, default 649121): 
Using default value 649121
Last cylinder, +cylinders or +size{K,M,G} (649121-1040253, default 1040253): 
Using default value 1040253

Command (m for help): p　　　　--打印分区信息

Disk /dev/vdb: 536.9 GB, 536870912000 bytes
16 heads, 63 sectors/track, 1040253 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x9f199567

   Device Boot      Start         End      Blocks   Id  System
/dev/vdb1               1      624153   314573080+  83  Linux
/dev/vdb2          624154      649120    12583368   83  Linux
/dev/vdb3          649121     1040253   197131032   83  Linux

Command (m for help): w　　　　　　--保存分区
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

 注意：发现有些时候系统并没有自动的将分区信息同步给Linux内核，而且这种情况似乎还比较常见，但不能算作是严重的bug，因为如果设备信息没有被抽象为文件，我们也可以输入partprobe命令来手动的同步信息到内核，而且一般推荐敲击两次会效果更佳，但一旦遇到连这个命令都不能解决的时候，咱们就重启计算机吧，这个方法一定会有用的。

 [root@app-01 ~]# file /dev/sdb1
　　/dev/sdb2: cannot open (No such file or directory)
 [root@app-01 ~]# partprobe
 [root@app-01 ~]# partprobe
 [root@app-01 ~]# file /dev/sdb1
　　/dev/sdb1: block special

2.格式化分区

--格式化普通分区

mkfs.ext4 /dev/vdb1
mkfs.ext4 /dev/vdb3

--格式化swap分区

[root@app-01 ~]# mkswap /dev/vdb2
Setting up swapspace version 1, size = 12583364 KiB
no label, UUID=5f48bdfe-81a8-43a1-b9dc-45ed9b21124f

3.挂载分区

--建立挂载目录

[root@app-01 ~]# mkdir /u01
[root@app-01 ~]# mkdir /u02

--挂载普通分区

[root@app-01 ~]# mount /dev/vdb1 /u01
[root@app-01 ~]# mount /dev/vdb3 /u02

--挂载swap

[root@app-01 ~]# swapon /dev/vdb2
[root@app-01 ~]# free -m
             total       used       free     shared    buffers     cached
Mem:          7872        774       7097          0         86        482
-/+ buffers/cache:        205       7666
Swap:        12288          0      12288

4.设置开机自动挂载

/dev/vdb1               /u01                    ext4    defaults        0 0
/dev/vdb3               /u02                    ext4    defaults        0 0
/dev/vdb2               swap                    swap    defaults        0 0 

 5.查看磁盘的UUID

方法一：

[root@app-01 jdk1.7.0_80]# ll /dev/disk/by-uuid/
total 0
lrwxrwxrwx 1 root root 10 Feb 22 11:02 0ac3b66b-c1c6-4838-b13f-fdf5ee066c26 -> ../../vdb3
lrwxrwxrwx 1 root root 10 Feb 22 11:08 1fd6f7f3-a722-4637-91de-327d32c3e05b -> ../../vdb1
lrwxrwxrwx 1 root root 10 Feb 22 11:00 5f48bdfe-81a8-43a1-b9dc-45ed9b21124f -> ../../vdb2
lrwxrwxrwx 1 root root 10 Feb 22 10:48 80b9b662-0a1d-4e84-b07b-c1bf19e72d97 -> ../../vda1

方法二：

[root@app-01 jdk1.7.0_80]# blkid /dev/vdb1
/dev/vdb1: UUID="1fd6f7f3-a722-4637-91de-327d32c3e05b" TYPE="xfs"