2023年12月23日发(作者：)

原来linux不用LVM也能扩展文件系统

以前总以为UNIX/LINUX使用了lvm才能扩展或缩小卷和文件系统，今天才发现我错了：即使没有lvm，linux也能扩展卷和及其相应的文件系统而不会丢失原有数据。

以下是测试步骤，记录备查。

1、系统是redhatlinux 6

[root@localhostku]# uname -r

6.x86_64

[root@localhostku]# more /etc/redhat-release

Red Hat Enterprise Linux Server release 6.1 (Santiago)

[root@localhostku]#

2、创建/dev/sdb1及其文件系统，创建文本文件

[root@localhostku]# echo welcome to redhat world >ricky

[root@localhostku]# more ricky

welcome to redhat world

3、目前/dev/sdb1对应的文件系统/ku为1.2G

[root@localhostku]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

16G 3.7G 11G 25% /

tmpfs 613M 88K 613M 1% /dev/shm

/dev/sda1 485M 32M 428M 7% /boot

/dev/sdb1 1.2G 34M 1.1G 3% /ku

4、卸载/ku

[root@localhostku]# cd /

[root@localhost /]# umount /ku

[root@localhost /]#

5、用fdisk命令删除/dev/sdb1分区，然后重新创建/dev/sdb1分区，并指定大小为4G

[root@localhost /]# fdisk /dev/sdb

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): p

Disk /dev/sdb: 5368 MB, 5368709120 bytes

255 heads, 63 sectors/track, 652 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: 0x54f7c6df

Device Boot Start End Blocks Id System

/dev/sdb1 1 393 3156741 83 Linux

Command (m for help): d

Selected partition 1

Command (m for help): n

Command action

e extended

p primary partition (1-4)

p

Partition number (1-4): 1

First cylinder (1-652, default 1):

Using default value 1

Last cylinder, +cylinders or +size{K,M,G} (1-652, default 652): +4G

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

Syncing disks.

[root@localhost /]#

6、fdisk -l /dev/sdb输出可以看出，cylinder已经由393扩为523

[root@localhost /]# fdisk -l /dev/sdb

Disk /dev/sdb: 5368 MB, 5368709120 bytes

255 heads, 63 sectors/track, 652 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: 0x54f7c6df

Device Boot Start End Blocks Id System

/dev/sdb1 1 523 4200966 83 Linux

7、先check文件系统

[root@localhost /]# e2fsck -f /dev/sdb1

e2fsck 1.41.12 (17-May-2010)

Pass 1: Checking inodes, blocks, and sizes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Pass 4: Checking reference counts

Pass 5: Checking group summary information

/dev/sdb1: 12/73760 files (0.0% non-contiguous), 13234/307200 blocks

8、将文件系统resize为2G

[root@localhost /]# resize2fs /dev/sdb1 2G

resize2fs 1.41.12 (17-May-2010)

Resizing the filesystem on /dev/sdb1 to 524288 (4k) blocks.

The filesystem on /dev/sdb1 is now 524288 blocks long.

[root@localhost /]# mount /dev/sdb1 /ku

[root@localhost /]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

16G 3.7G 11G 25% /

tmpfs 613M 88K 613M 1% /dev/shm

/dev/sda1 485M 32M 428M 7% /boot

/dev/sdb1 2.0G 34M 1.9G 2% /ku

[root@localhost /]#

9、检查扩容前的文件是否正确无损

[root@localhost /]# cd /ku

[root@localhostku]# more ricky

welcome to redhat world

[root@localhostku]#

10、当然也可以在线扩展文件系统

[root@localhostku]# resize2fs /dev/sdb1 2500M

resize2fs 1.41.12 (17-May-2010)

Filesystem at /dev/sdb1 is mounted on /ku; on-line resizing required

old desc_blocks = 1, new_desc_blocks = 1

Performing an on-line resize of /dev/sdb1 to 640000 (4k) blocks.

The filesystem on /dev/sdb1 is now 640000 blocks long.

[root@localhostku]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

16G 3.7G 11G 25% /

tmpfs 613M 88K 613M 1% /dev/shm

/dev/sda1 485M 32M 428M 7% /boot

/dev/sdb1 2.5G 34M 2.3G 2% /ku

[root@localhostku]#

11、但是不可以在线缩小；要缩小文件系统必须先卸载文件系统

[root@localhostku]# resize2fs /dev/sdb1 1G

resize2fs 1.41.12 (17-May-2010)

Filesystem at /dev/sdb1 is mounted on /ku; on-line resizing required

On-line shrinking from 640000 to 262144 not supported.

[root@localhostku]# cd /

[root@localhost /]# umount /ku

[root@localhost /]# resize2fs /dev/sdb1 1G

resize2fs 1.41.12 (17-May-2010)

Please run 'e2fsck -f /dev/sdb1' first.

[root@localhost /]# e2fsck -f /dev/sdb1

e2fsck 1.41.12 (17-May-2010)

Pass 1: Checking inodes, blocks, and sizes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Pass 4: Checking reference counts

Pass 5: Checking group summary information

/dev/sdb1: 12/147520 files (0.0% non-contiguous), 17864/640000 blocks

[root@localhost /]# resize2fs /dev/sdb1 1G

resize2fs 1.41.12 (17-May-2010)

Resizing the filesystem on /dev/sdb1 to 262144 (4k) blocks.

The filesystem on /dev/sdb1 is now 262144 blocks long.

[root@localhost /]# mount /dev/sdb1 /ku

[root@localhost /]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

16G 3.7G 11G 25% /

tmpfs 613M 88K 613M 1% /dev/shm

/dev/sda1 485M 32M 428M 7% /boot

/dev/sdb1 1010M 34M 939M 4% /ku

12、当然，你不能将文件系统扩展为比它的逻辑卷大

[root@localhost /]# resize2fs /dev/sdb1 5G

resize2fs 1.41.12 (17-May-2010)

The containing partition (or device) is only 1050241 (4k) blocks.

You requested a new size of 1310720 blocks.

LVM是Logical Volume Manager(逻辑卷管理器)的简写，它为主机提供了更高层次的磁盘存储管理能力。LVM可以帮助系统管理员为应用与用户方便地分配存储空间。在LVM管理下的逻辑卷可以按需改变大小或添加移除。另外，LVM可以为所管理的逻辑卷提供定制的命名标识。因此，使用LVM主要是方便了对存储系统的管理，增加了系统的扩展性。

一、准备lvm环境

1．硬盘的准备

添加了一块硬盘/dev/hdb。

准备了三个分区，方案如下：容量为100M，仅为了实验准备。

/dev/hdb1

/dev/hdb2

/dev/hdb3

2．转换分区类型为lvm卷

fdisk /dev/hdb

t转换为lvm卷类型

Device Boot Start End Blocks Id System

/dev/hdb1 1 208 98248+ 8e Linux LVM

/dev/hdb2 209 416 98280 8e Linux LVM

/dev/hdb3 417 624 98280 8e Linux LVM

然后w保存并且

#partprobe /*使用磁盘分区生效*/

二、lvm创建过程

1.从硬盘驱动器分区中创建物理卷(physical volumes-PV)。

2.从物理卷中创建卷组(volume groups-VG)

3.从卷组中创建逻辑卷(logical volumes-LV)，并分派逻辑卷挂载点，其中只有逻辑卷才可以写数据。

lvm的最大的特点就是可以动态的调整分区的大小，并且可以随着分区容量的增长而增加磁盘空间的容量。

LVM配置与创建

三、LVM的物理卷PV

1．相关命令

pvcreate创建PV

pvscan扫描PV

pvdisplay显示PV

pvremove删除PV

partprobe

2．创建物理卷

如果以上容量不够，可以再添加其它分区到物理卷中。

[root@redhat ~]# pvcreate /dev/hdb1 /dev/hdb2

Physical volume “/dev/hdb1″ successfully created

Physical volume “/dev/hdb2″ successfully created

[root@redhat ~]# pvscan

PV /dev/hdb1 lvm2 [95.95 MB]

PV /dev/hdb2 lvm2 [95.98 MB]

Total: 2 [191.92 MB] / in use: 0 [0 ] / in no VG: 2 [191.92 MB]

[root@redhat ~]# pvdisplay

— NEW Physical volume —

PV Name /dev/hdb1

VG Name

PV Size 95.95 MB

Allocatable NO

PE Size (KByte) 0

Total PE 0

Free PE 0

Allocated PE 0

PV UUID 2Ni0Tx-oeSy-zGUP-t7KG-Fh22-0BUi-iyPhhQ

— NEW Physical volume —

PV Name /dev/hdb2

VG Name

PV Size 95.98 MB

Allocatable NO

PE Size (KByte) 0

Total PE 0

Free PE 0

Allocated PE 0

PV UUID 2XLXfY-V3L2-Mtsl-79U4-ovuJ-YaQf-YV9qHs

四、创建LVM的卷组VG

1．相关命令

vgcreate创建VG

vgscan扫描VG

vgdispaly

vgextend

vgreduce

vgchange

vgremove

2．创建逻辑卷VG

[root@redhat ~]# vgcreate vg0 /dev/hdb1 /dev/hdb2

Volume group “vg0″ successfully created

[root@redhat ~]# vgscan

Reading all physical volumes. This may take a while…

Found volume group “vg0″ using metadata type lvm2

[root@redhat ~]# vgdisplay

— Volume group —

VG Name vg0

System ID

Format lvm2

Metadata Areas 2

Metadata Sequence No 1

VG Access read/write

VG Status resizable

MAX LV 0

Cur LV 0

Open LV 0

Max PV 0

Cur PV 2

Act PV 2

VG Size 184.00 MB

PE Size 4.00 MB /*分配的块的大小默认为4M*/

Total PE 46

Alloc PE / Size 0 / 0

Free PE / Size 46 / 184.00 MB

VG UUID kL5CGk-5Odk-r3PK-9q0A-s94h-OHv4-BojBnH增加VG容量到1TB的方法：

vgcreate -s 16M vg0 /dev/hdb1 /dev/hdb2

3．删除与添加逻辑卷

[root@redhat ~]# vgreduce vg0 /dev/hdb2

Removed “/dev/hdb2″ from volume group “vg0″

[root@redhat ~]# vgextend vg0 /dev/hdb2

Volume group “vg0″ successfully extended

五、创建LVM的逻辑卷LV

1．相关命令

lvcreate

lvscan

lvdisplay

lvextend

lvreduce

lvremove

lvresize

2．创建逻辑卷LV

[root@redhat ~]# lvcreate -L 184M -n data vg0

Logical volume “data” created

[root@redhat ~]# lvscan

ACTIVE „/dev/vg0/data‟ [184.00 MB] inherit

[root@redhat ~]# lvdisplay

— Logical volume —

LV Name /dev/vg0/data

VG Name vg0

LV UUID HNKO5d-yRre-qVnP-ZT8D-fXir-XTeM-r6WjDX

LV Write Access read/write

LV Status available

# open 0

LV Size 184.00 MB

Current LE 46

Segments 2

Allocation inherit

Read ahead sectors 0

Block device 253:0

六、挂载LVM的逻辑卷LV

lv的格式化:

3 /dev/vg0/data

mdkir /mnt/lvm

mount /dev/vg0/data /mnt/lvm

[root@redhat ~]# ls /mnt/lvm

lost+found

[root@redhat ~]# df -T

文件系统类型 1K-块已用可用已用% 挂载点

/dev/hda3 ext3 7625092 2219460 5012040 31% /

/dev/hda1 ext3 101086 10006 85861 11% /boot

tmpfstmpfs 150108 0 150108 0% /dev/shm

/dev/mapper/vg0-data

ext3 182469 5664 167385 4% /mnt/lvm

七、LVM的容量调整

LVM的容量调整可以在多个环节进行调整，比如：可以在物理卷上，VG上，以及LV上，都可以进行容量的扩展，这也是LVM它的一个优势所在。

1．添加物理卷

首先应卸载在使用过程中的LV，然后必须保证该磁盘的类型是lvm类型，才能添加进来。

[root@redhat ~]# umount /dev/vg0/data

[root@redhat ~]# pvcreate /dev/hdb3

Physical volume “/dev/hdb3″ successfully created

[root@redhat ~]# pvscan

PV /dev/hdb1 VG vg0 lvm2 [92.00 MB / 0 free]

PV /dev/hdb2 VG vg0 lvm2 [92.00 MB / 0 free]

PV /dev/hdb3 lvm2 [95.98 MB]

Total: 3 [279.98 MB] / in use: 2 [184.00 MB] / in no VG: 1 [95.98 MB]

2．添加VG的容量

把上面新添加的LVM磁盘加入到vg0卷组中。

[root@redhat ~]# vgextend vg0 /dev/hdb3

Volume group “vg0″ successfully extended

[root@redhat ~]# vgdisplay

— Volume group —

VG Name vg0

System ID

Format lvm2

Metadata Areas 3

Metadata Sequence No 5

VG Access read/write

VG Status resizable

MAX LV 0

Cur LV 1

Open LV 0

Max PV 0

Cur PV 3

Act PV 3

VG Size 276.00 MB

PE Size 4.00 MB

Total PE 69

Alloc PE / Size 46 / 184.00 MB

Free PE / Size 23 / 92.00 MB

VG UUID kL5CGk-5Odk-r3PK-9q0A-s94h-OHv4-BojBnH

3．添加入LV中VG增珈的容量

把新加入LVM磁盘的容量加入LV中。

[root@redhat ~]# lvextend -L +92M /dev/vg0/data

Extending logical volume data to 276.00 MB

Logical volume data successfully resized

[root@redhat ~]# lvscan

ACTIVE „/dev/vg0/data‟ [276.00 MB] inherit

[root@redhat ~]# resize2fs -f /dev/vg0/data

resize2fs 1.39 (29-May-2006)

Resizing the filesystem on /dev/vg0/data to 282624 (1k) blocks.

The filesystem on /dev/vg0/data is now 282624 blocks long.

如果不做这一步的话，在实现挂载的时候，发现LV的容量没有真正的加入进LV卷中，因为相关信息写入到了磁盘超级块中。

4．挂载使用

[root@redhat ~]# mount /dev/vg0/data /mnt/lvm

[root@redhat ~]# df

文件系统 1K-块已用可用已用% 挂载点

/dev/hda3 7625092 2219468 5012032 31% /

/dev/hda1 101086 10006 85861 11% /boot

tmpfs 150108 0 150108 0% /dev/shm

/dev/mapper/vg0-data 273569 6168 256097 3% /mnt/lvm

LVM的卸载

八、LVM的卸载方法

如果不想使用LVM的话,可以卸载它, 卸载的方法与分区的删除方法类似，就是最后创建的最先删除。顺序如下：

先删除LV

再删除VG

最后PV

以前的LVM的分区应用fdisk转换成其它类型的文件系统，当普通分区使用。

九、LVM的卸载过程

1．umount取消挂载

[root@redhat ~]# df

文件系统 1K-块已用可用已用% 挂载点

/dev/hda3 7625092 2219468 5012032 31% /

/dev/hda1 101086 10006 85861 11% /boot

tmpfs 150108 0 150108 0% /dev/shm

/dev/mapper/vg0-data 273569 6168 256097 3% /mnt/lvm

[root@redhat ~]# umount /mnt/lvm

2．删除LV逻辑卷

[root@redhat ~]# lvremove /dev/vg0/data

Do you really want to remove active logical volume “data”? [y/n]: y

Logical volume “data” successfully removed

3．删除VG卷组

[root@redhat ~]# vgchange -a n vg0

0 logical volume(s) in volume group “vg0″ now active

说明：把vg0转换成休眠状态，实验中这一步可以不用。

[root@redhat ~]# vgremove vg0

Volume group “vg0″ successfully removed

4．删除PV

[root@redhat ~]# pvscan查看pv的情况

PV /dev/hdb1 lvm2 [95.95 MB]

PV /dev/hdb2 lvm2 [95.98 MB]

PV /dev/hdb3 lvm2 [95.98 MB]

Total: 3 [287.90 MB] / in use: 0 [0 ] / in no VG: 3 [287.90 MB]

[root@redhat ~]# pvremove /dev/hdb1 /dev/hdb2 /dev/hdb3

Attempt to close device „/dev/cdrom‟ which is not open.

Labels on physical volume “/dev/hdb1″ successfully wiped

Labels on physical volume “/dev/hdb2″ successfully wiped

Labels on physical volume “/dev/hdb3″ successfully wiped

5．最后就是用fdisk修改磁盘的类型了。