Linux下如何挂载磁盘[通俗易懂]

大家好，又见面了，我是你们的朋友全栈君。

使用虚拟机时发现磁盘空间不够了，需要挂载一个磁盘以供继续使用，但是磁盘不是添加就可以使用的，还需要进行挂载。

一、添加磁盘

添加加新硬盘重启服务器

添加完之后就可以重启机器了，如果你机器是开启的，进入系统并不能看见你刚添加的那块磁盘，只有等系统重启，重新加载之后才会显示安装的那块磁盘

二、进入系统

使用root用户进入系统

三、 查看硬盘信息

[root@localhost ~]# fdisk -l //磁盘命令

Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0x000c4cb5

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          64      512000   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              64        2611    20458496   8e  Linux LVM

Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0xd0f5c869

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        2610    20964793+  83  Linux

Disk /dev/sdc: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0x00000000

可以看到这台机器加载了三个磁盘sda、sdb、sdc
其中sda是初始磁盘，sdb已经初始化且经过使用，sdc是刚刚加载的，未格式化的新磁盘

四、创建新硬盘分区

[root@localhost ~]# fdisk /dev/sdc #进入磁盘
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x45a3cadb.
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): m
Command action
   a   toggle a bootable flag      #设定可启动标记
   b   edit bsd disklabel
   c   toggle the dos compatibility flag
   d   delete a partition          #删除一个分区
   l   list known partition types  #各分区类型所对应的ID
   m   print this menu             #菜单
   n   add a new partition         #添加一个分区
   o   create a new empty DOS partition table
   p   print the partition table   #显示该磁盘下的当前分区信息
   q   quit without saving changes #不保存退出
   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 #保存退出
   x   extra functionality (experts only)

知道命令之后就可以进行分区了

Command (m for help): p //打印分区信息,可以看到当前并没有分区

Disk /dev/sdc: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0x45a3cadb

   Device Boot      Start         End      Blocks   Id  System

Command (m for help): n //创建一个新的分区
Command action
   e   extended//输入e为创建扩展分区 
   p   primary partition (1-4) //输入p为创建逻辑分区 
p
Partition number (1-4): 1//划分逻辑分区
First cylinder (1-2610, default 1): //我这里直接回车,是不想把该磁盘分成多个分区,把整个磁盘作为1个分区
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): 
Using default value 2610

Command (m for help): p //再次查看可以看到该磁盘已经有1个分区了

Disk /dev/sdc: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0x45a3cadb

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1        2610    20964793+  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.

再次使用”fdisk -l”命令查看磁盘信息

Disk /dev/sdc: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0x406a4c58

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1        2610    20964793+  83  Linux

第三块磁盘/dev/sdc已经分区好了

五、格式化分区

[root@localhost ~]# mkfs.ext3 /dev/sdc1
//将/dev/sdc1格式化为ext3类型,好像大部分的磁盘都是格式化为ext3类型,具体为什么没有深入研究,暂时不清楚,想了解的朋友可以自己查一下

[root@localhost ~]# mkfs.ext3 /dev/sdc1
mke2fs 1.41.12 (17-May-2010)
文件系统标签=
操作系统:Linux
块大小=4096 (log=2)
分块大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1310720 inodes, 5241198 blocks
262059 blocks (5.00%) reserved for the super user
第一个数据块=0
Maximum filesystem blocks=4294967296
160 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
    32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
    4096000

正在写入inode表: 完成                            
Creating journal (32768 blocks): 完成
Writing superblocks and filesystem accounting information: 完成

This filesystem will be automatically checked every 31 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

格式化完毕，此时就可以使用“mount”命令挂载分区了，然后使用这个磁盘空间了

六、挂载分区以及开机自动挂载

[root@localhost ~]# df -h //此时只有sda1和sdb1两个磁盘挂载
Filesystem                    Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 18G 15G 1.5G 92% /
tmpfs                         932M   76K  932M   1% /dev/shm
/dev/sda1                     485M   40M  421M   9% /boot
/dev/sdb1                      20G  1.2G   18G   7% /disk/diskone
/dev/sr0                      4.2G  4.2G     0 100% /media/CentOS_6.5_Final
[root@localhost /]# cd /disk/
[root@localhost disk]# ll
总用量 4
drwxr-xr-x. 4 root root 4096 7月  28 17:04 diskone
[root@localhost disk]# cd diskone/
[root@localhost diskone]# ll
总用量 20
drwx------. 2 root root 16384 7月  28 16:12 lost+found
drwxr-xr-x. 2 root root  4096 7月  28 17:09 software
[root@localhost diskone]# cd ../
[root@localhost disk]# mkdir disktwo //创建被挂载的路径
[root@localhost disk]# ll
总用量 8
drwxr-xr-x. 4 root root 4096 7月  28 17:04 diskone
drwxr-xr-x. 2 root root 4096 8月   1 16:48 disktwo
[root@localhost disk]# mount /dev/sdc1 /disk/disktwo/ //进行挂载
[root@localhost disk]# df -h //再次查看,发现sdc1已经挂载在/disk/disktwo路径下
Filesystem                    Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 18G 15G 1.5G 92% /
tmpfs                         932M   76K  932M   1% /dev/shm
/dev/sda1                     485M   40M  421M   9% /boot
/dev/sdb1                      20G  1.2G   18G   7% /disk/diskone
/dev/sr0                      4.2G  4.2G     0 100% /media/CentOS_6.5_Final
/dev/sdc1                      20G  173M   19G   1% /disk/disktwo

磁盘已经挂载上了
下面设置开机自动挂载
编辑/etc/fstab文件，再最后面添加
/dev/sdc1(磁盘分区) /disk/disktwo（挂载目录） ext3（文件格式）defaults 0 0

vim /etc/fstab
/dev/sdc1(磁盘分区)  /disk/disktwo（挂载目录） ext3（文件格式）defaults  0  0

之后重启就OK啦！！！