LVM_resize+根目录下各个目录的作用

Today I felt happy because I solved a problem on LVM resizing which defeated me last time I came across it.It felt good to conquer it.Now I will describe the problem.

As time goes by,the data on my /home is booming and It is said that the free space of the /home is low.

Here is my partition structure:

lv lv_var250G(mount /var) lv_home200G(mount /home)

vg vg01

pv /dev/sda1

Clearly,my partition is not wise because the /var doesn’t need so many space.

So I wanna shrank the /var and extend the /home.

I tried it in the winter holiday but failed.And finally I have to reinstall the virtual machine.

The right sequence of the LVM_resize is below.

Because the /var stores

/var 某些大文件的溢出区，比如说各种服务的日志

/mnt 供用户临时挂载其他文件系统

/tmp 共用的临时文件存储点

/lost+found非正常关机留下的“无家可归”的文件

/proc 虚拟的目录，是系统内存的映射，可以直接访问这个目录来获取系统信息

/usr 要用到的应用程序和文件几乎都在这个目录

/usr/bin 众多应用

/bin 二进制可执行命令

–/sbin 系统管理命令

-/usr/sbin 超级用户的管理程序

-/usr/doc linux文档

-/usr/includeLinux开发头文件

-/usr/lib 常用的动态链接库和软件包配置文件

-/usr/src 源代码

-/usr/local/bin

-/usr/local/lib 本地增加的命令，库根文件系统

/lib 跟文件系统所需要的共享库，存放了很多跟文件系统程序运行所需的共享文件，包括很多共享代码

/lib/modules 包括了很多系统核心可加载的各种模块，尤其是再回敷系统重新引导需要的

/var is important,and if we try to umount /var ,it is reported that /var is busy.

So we have to enter LiveCD mode to do LVM_resize.

Make sure you have installed the lvm2–Linux Logical Volumn Manager then use lvscan to see the situation.

To shrank a file system you should use resize2fs (man it to see how to use it)

then lvreduce (also man)

PAY ATTENTION you should shrank the file system first.

To extend a file system you should use lvextend then resize2fs.（root）

Then don’t forget to lvchange!!!

Look back on this journey,it is clear and easy.But I actually came across a series of problems.