Linux挂载卸载硬盘
虚拟机操作演示
1. 启动VM,给Linux添加一块硬盘
2. fdisk -l通常会看到一块新的硬盘/dev/sdb
Disk /dev/sda: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda3 14 1044 8281507+ 83 Linux
Disk /dev/sdb: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdb doesn't contain a valid partition table3.分区
[root@localhost ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won't be recoverable.
The number of cylinders for this3. disk is set to 1044.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
Command (m for help): m ##在这里按m ，就会输出帮助；
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition ##这是删除一个分区的动作；
l list known partition types ##：l是列出分区类型，以供我们设置相应分区的类型；
m print this menu
n add a new partition ##添加一个分区；
o create a new empty DOS partition table
p print the partition table ##p列出分区表；
q quit without saving changes ##不保存退出；
s create a new empty Sun disklabel
t change a partition's system id ##t 改变分区类型；
u change display/entry units
v verify the partition table
w write table to disk and exit ##把分区表写入硬盘并退出；
x extra functionality (experts only) ##扩展应用，专家功能；
Command (m for help): n
Command action
e extended ##扩展分区
p primary partition (1-4) ##选p建主分区
p
Partition number (1-4): 1
First cylinder (1-17849, default 1): ##注：这个就是分区的Start 值；这里最好直接按回车，如果你输入了一个非默认的数字，会造成空间浪费；
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-17849, default 17849): 8920
Using default value 500
##这个是定义分区大小的，+200M 就是大小为200M ；当然你也可以根据上面提示的单位cylinder的大小来算，然后来指定 End的数值，在fdisk –l命令中可以看到Units = cylinders of 16065 * 512 = 8225280 bytes，这个就是单位cylinder的大小，我这里选的End的数值是8920，正好是总大小的一半，71G左右
##然后再来建一个主分区
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (8921-17849, default 8921):8921
Using default value 8921
Last cylinder or +size or +sizeM or +sizeK (8921-17849, default 17849):17849
Using default value 17849
##最后保存并退出，切记，一定要保存，不然不会生效的。
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.4. 使用fdisk –l命令来查看磁盘状况：
[root@localhost ~]# fdisk -l
Disk /dev/sda: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda3 14 1044 8281507+ 83 Linux
Disk /dev/sdb: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 1 8920 71649868+ 83 Linux
/dev/sdb2 8921 17849 71722192+ 83 Linux 磁盘/dev/sdb已经被划分为2个分区，每个分区大小大概是71G左右。
在挂载文件系统之前，需要将/dev/sdb1和/dev/sdb2重新用mkfs -t ext3命令格式化一下，否则在挂载时会报错。
5. 格式化分区：使用mkfs.ext4 /dev/sdb命令格式化磁盘
注：也可以使用mkfs -t ext3 /dev/sdb命令
[root@localhost ~]# mkfs -t ext3 /dev/sdb1 ##指将该磁盘格式化成ext3文件系统
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
1048576 inodes, 2096474 blocks
104823 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2147483648
64 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 31 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.6. 挂载
挂载文件系统，目前有两种方法：
- 一是通过 mount 来挂载,使用mount挂载系统，一旦系统重启之后就需要重新挂载。
- 二是通过/etc/fstab文件来开机自动挂载。我把/dev/sdb1挂载到/test下
[root@localhost ~]# mkdir /test ## 首先建立挂载的目录test
(或者[root@localhost ~]# cd /
[root@localhost ~]# mkdir test
)
[root@localhost ~]# df –h ##挂载前的分区
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
6.7G 5.8G 576M 92% /
/dev/sda1 99M 12M 82M 13% /boot
tmpfs 233M 0 233M 0% /dev/shm
[root@localhost ~]# mount /dev/sdb1 /test
[root@localhost ~]# df –h ##挂载后的分区
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
6.7G 5.8G 576M 92% /
/dev/sda1 99M 12M 82M 13% /boot
tmpfs 233M 0 233M 0% /dev/shm
/dev/sdb1 7.9G 147M 7.4G 2% /test7. 通过/etc/fstab文件来开机自动挂载(不然重启电脑后系统将不会保存之前的挂载操作):
[root@localhost ~]# vi /etc/fstab
/dev/VolGroup00/LogVol00 / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
devpts /dev/pts devpts gid=5,mode=620 0 0
tmpfs /dev/shm tmpfs defaults 0 0
proc /proc proc defaults 0 0
sysfs /sys sysfs defaults 0 0
/dev/VolGroup00/LogVol01 swap swap defaults 0 0
/dev/sdb1 /test ext3 defaults 1 1
/dev/sdb2 /test ext3 defaults 1 1
# Beginning of the block added by the VMware software
.host:/ /mnt/hgfs vmhgfs defaults,ttl=5 0 0
# End of the block added by the VMware software- 第一字段：设备名，在这里表示是文件系统； 有时我们把挂载文件系统也说成挂载分区；
- 第二字段：文件系统的挂载点；
- 第三字段：文件系统类型；
- 第四字段：mount 命令的选项，和mount 中的-o 同理；defaults包括这些选项 rw, suid, dev, exec, auto, nouser, async；
- 第五字段：表示文件系统是否需要dump 备份，1是需要，0 是不需要；
- 第六字段： 是否在系统启动时，通过fsck磁盘检测工具来检查文件系统，1是需要，0是不需要，2是跳过；
8. 卸载：
[root@localhost ~]# umount /dev/sdb1
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
6.7G 5.8G 576M 92% /
/dev/sda1 99M 12M 82M 13% /boot
tmpfs 233M 0 233M 0% /dev/shm