LVM的基本应用、扩展及缩减实现

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crcr7 2015-08-31 21:53:17 ©著作权

文章标签 linux 马鹏飞 LVM 逻辑卷管理 文章分类 运维

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LVM :

Logical Volume Manager 逻辑卷管理，它是一种可以用在Linux内核的逻辑分卷管理器，常用于管理磁盘和其他大型存储设备上。

LVM的应用：

在生产环境中常见于增加磁盘，可将多个磁盘合理的合并成一个或多个，但又不会影响业务的进行。

与raid的区别：

LVM是软件的卷管理方式，而RAID是磁盘保护的方法。对于重要的业务来说，一般是同时存在。RAID用来保护物理的磁盘不会因为故障而中断业务。LVM用来实现对卷的良性的管理，更好的利用磁盘资源。

LVM的扩展及缩减实例：

1，首先查看逻辑卷容量
[root@bogon ~]# df -h
Filesystem            Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                       39G 461M   37G   2% /
/dev/mapper/VolGroup00-LogVol03
                       64G 222M   61G   1% /var
/dev/mapper/VolGroup00-LogVol02
                       49G 2.0G   45G   5% /usr
/dev/mapper/VolGroup00-LogVol01
                       39G 177M   37G   1% /home
/dev/sda1              99M   13M   82M 14% /boot
tmpfs                1005M     0 1005M   0% /dev/shm
/dev/hdc              3.5G 3.5G     0 100% /media

2，在home下有lost+found可以看到home分区单独挂载到一个分区下面
[root@bogon ~]# ls /home/
innofidei lost+found

3，卸载并验证
[root@bogon ~]# umount /dev/mapper/VolGroup00-LogVol01
[root@bogon ~]# ls /home/

4，resize2fs 卷组
[root@bogon ~]# resize2fs /dev/mapper/VolGroup00-LogVol01 20G
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/mapper/VolGroup00-LogVol01 to 5242880 (4k) blocks.
The filesystem on /dev/mapper/VolGroup00-LogVol01 is now 5242880 blocks long.
注意这里会提醒你e2fsck的
所以resize2fs之前要这样做： e2fsck -f /dev/mapper/VolGroup-logVol01

5，缩减lvm
[root@bogon ~]# lvreduce -L 20G /dev/mapper/VolGroup00-LogVol01
/dev/hdc: open failed: Read-only file system
WARNING: Reducing active logical volume to 20.00 GB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce LogVol01? [y/n]: y
Reducing logical volume LogVol01 to 20.00 GB
Logical volume LogVol01 successfully resized

6,重新挂载并验证
[root@bogon ~]# mount -a
[root@bogon ~]# df -h
Filesystem            Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                       39G 461M   37G   2% /
/dev/mapper/VolGroup00-LogVol03
                       64G 222M   61G   1% /var
/dev/mapper/VolGroup00-LogVol02
                       49G 2.0G   45G   5% /usr
/dev/sda1              99M   13M   82M 14% /boot
tmpfs                1005M     0 1005M   0% /dev/shm
/dev/hdc              3.5G 3.5G     0 100% /media
/dev/mapper/VolGroup00-LogVol01
                       20G 173M   19G   1% /home
[root@bogon ~]# ls /home/
innofidei lost+found

7，扩展另一lvm
[root@bogon ~]# lvextend -L +20G /dev/mapper/VolGroup00-LogVol02
/dev/hdc: open failed: Read-only file system
Extending logical volume LogVol02 to 70.00 GB
Logical volume LogVol02 successfully resized
[root@bogon ~]# resize2fs /dev/mapper/VolGroup00-LogVol02
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/mapper/VolGroup00-LogVol02 is mounted on /usr; on-line resizing required
Performing an on-line resize of /dev/mapper/VolGroup00-LogVol02 to 18350080 (4k) blocks.
The filesystem on /dev/mapper/VolGroup00-LogVol02 is now 18350080 blocks long.

8,再验证
[root@bogon ~]# df -h
Filesystem            Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                       39G 461M   37G   2% /
/dev/mapper/VolGroup00-LogVol03
                       64G 222M   61G   1% /var
/dev/mapper/VolGroup00-LogVol02
                       68G 2.0G   63G   4% /usr
/dev/sda1              99M   13M   82M 14% /boot
tmpfs                1005M     0 1005M   0% /dev/shm
/dev/hdc              3.5G 3.5G     0 100% /media
/dev/mapper/VolGroup00-LogVol01
                       20G 173M   19G   1% /home