LVM(Logical Volume Manager)邏輯卷管理是在Linux2.4核心以上實現的磁碟管理技術。LVM將一個或多個硬碟的分割槽在邏輯上集合，相當於一個大硬碟來使用，當硬碟的空間不夠使用的時候，可以繼續將其它的硬碟的分割槽加入其中，這樣可以實現磁碟空間的動態管理，相對於普通的磁碟分割槽有很大的靈活性。與傳統的磁碟與分割槽相比，LVM為計算機提供了更高層次的磁碟儲存。它使系統管理員可以更方便的為應用與使用者分配儲存空間。在LVM管理下的儲存卷可以按需要隨時改變大小與移除(可能需對檔案系統工具進行升級)。LVM也允許按使用者組對儲存捲進行管理，允許管理員用更直觀的名稱(如"data'、 'oracle')代替物理磁碟名(如'sda'、'sdb')來標識儲存卷。

物理儲存介質(The physical media)：這裡指系統的儲存裝置/dev/sda1、/dev/xvdb1等，是儲存系統最低層的儲存單元。

物理卷(physical volume)：物理卷就是指硬碟分割槽或從邏輯上與磁碟分割槽具有同樣功能的裝置(如RAID)，是LVM的基本儲存邏輯塊，但和基本的物理儲存介質(如分割槽、磁碟等)比較，卻包含有與LVM相關的管理引數，PV即物理的磁碟分割槽。

卷組(Volume Group)：LVM卷組類似於非LVM系統中的物理硬碟，其由物理卷組成，可以在卷組上建立一個或多個“LVM分割槽”（邏輯卷），LVM卷組由一個或多個物理卷組成。

邏輯卷（logical volume）：LVM的邏輯卷類似於非LVM系統中的硬碟分割槽，在邏輯卷之上可以建立檔案系統(比如/home或者/usr等)。

PE(physical extent)：每一個物理卷被劃分為稱為PE(Physical Extents)的基本單元，具有唯一編號的PE是可以被LVM定址的最小單元。PE的大小是可配置的，預設為4MB。

LE(logical extent)：邏輯卷也被劃分為被稱為LE(Logical Extents) 的可被定址的基本單位。在同一個卷組中，LE的大小和PE是相同的，並且一一對應。

建立PV

pvcreate /dev/xvdb1 /dev/xvdc1 /dev/xvde1

建立VG

vgcreate -s 8M datavg /dev/xvdb1 /dev/xvdc1 /dev/xvde1

建立LV

lvcreate -L 890G -n lvdata datavg

掛載LV

/dev/datavg/lvdata

建立PV

pvcreate /dev/xvdf1

擴充套件VG

vgextend datavg /dev/xvdf1

擴充套件LV

lvextend -L +100G /dev/datavg/lvdata

擴充套件檔案系統

resize2fs /dev/datavg/lvdata

案例：

[root@hkpgsadg dev]# ls -l /dev/xvd*

brw-rw---- 1 root disk 202, 0 Apr 13 16:37 /dev/xvda

brw-rw---- 1 root disk 202, 1 Apr 13 16:36 /dev/xvda1

brw-rw---- 1 root disk 202, 2 Apr 13 16:36 /dev/xvda2

brw-rw---- 1 root disk 202, 3 Apr 13 16:36 /dev/xvda3

brw-rw---- 1 root disk 202, 16 Apr 13 16:39 /dev/xvdb

brw-rw---- 1 root disk 202, 17 Apr 13 16:39 /dev/xvdb1

brw-rw---- 1 root disk 202, 32 Apr 13 16:37 /dev/xvdc

brw-rw---- 1 root disk 202, 64 Apr 13 16:37 /dev/xvde

brw-rw---- 1 root disk 202, 80 Apr 13 16:37 /dev/xvdf

[root@hkpgsadg dev]# fdisk /dev/xvdc

Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel

Building a new DOS disklabel with disk identifier 0x04acd4ca.

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): n

Command action

e extended

p primary partition (1-4)

p

Partition number (1-4): 1

First cylinder (1-65270, default 1):

Using default value 1

Last cylinder, +cylinders or +size{K,M,G} (1-65270, default 65270):

Using default value 65270

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

Syncing disks.

[root@hkpgsadg dev]# ls -l /dev/xvd*

brw-rw---- 1 root disk 202, 0 Apr 13 16:37 /dev/xvda

brw-rw---- 1 root disk 202, 1 Apr 13 16:36 /dev/xvda1

brw-rw---- 1 root disk 202, 2 Apr 13 16:36 /dev/xvda2

brw-rw---- 1 root disk 202, 3 Apr 13 16:36 /dev/xvda3

brw-rw---- 1 root disk 202, 16 Apr 13 16:39 /dev/xvdb

brw-rw---- 1 root disk 202, 17 Apr 13 16:39 /dev/xvdb1

brw-rw---- 1 root disk 202, 32 Apr 13 16:39 /dev/xvdc

brw-rw---- 1 root disk 202, 33 Apr 13 16:39 /dev/xvdc1

brw-rw---- 1 root disk 202, 64 Apr 13 16:40 /dev/xvde

brw-rw---- 1 root disk 202, 65 Apr 13 16:40 /dev/xvde1

brw-rw---- 1 root disk 202, 80 Apr 13 16:40 /dev/xvdf

brw-rw---- 1 root disk 202, 81 Apr 13 16:40 /dev/xvdf1

[root@hkpgsadg dev]# pvcreate /dev/xvdb1 /dev/xvdc1 /dev/xvde1

Physical volume "/dev/xvdb1" successfully created

Physical volume "/dev/xvdc1" successfully created

Physical volume "/dev/xvde1" successfully created

[root@hkpgsadg dev]# pvdisplay

--- Physical volume ---

PV Name /dev/xvda2

VG Name VolGroup

PV Size 19.51 GiB / not usable 3.00 MiB

Allocatable yes (but full)

PE Size 4.00 MiB

Total PE 4994

Free PE 0

Allocated PE 4994

PV UUID Tv6PfK-cNpj-zYU2-cPeY-Xp8H-guAW-YZOm7d

--- Physical volume ---

PV Name /dev/xvda3

VG Name VolGroup

PV Size 100.00 GiB / not usable 3.99 MiB

Allocatable yes (but full)

PE Size 4.00 MiB

Total PE 25599

Free PE 0

Allocated PE 25599

PV UUID hhOoov-6TnF-p1Mg-mPc6-66If-zNwT-v8cIKB

"/dev/xvdb1" is a new physical volume of "100.00 GiB"

--- NEW Physical volume ---

PV Name /dev/xvdb1

VG Name

PV Size 100.00 GiB

Allocatable NO

PE Size 0

Total PE 0

Free PE 0

Allocated PE 0

PV UUID OujuQi-rD1R-K91R-Ni82-jyAX-PpjD-ZnQvo5

"/dev/xvdc1" is a new physical volume of "499.99 GiB"

--- NEW Physical volume ---

PV Name /dev/xvdc1

VG Name

PV Size 499.99 GiB

Allocatable NO

PE Size 0

Total PE 0

Free PE 0

Allocated PE 0

PV UUID grJiiL-KGug-ef3c-XF2J-ffS1-AhTl-xfHSMW

"/dev/xvde1" is a new physical volume of "300.00 GiB"

--- NEW Physical volume ---

PV Name /dev/xvde1

VG Name

PV Size 300.00 GiB

Allocatable NO

PE Size 0

Total PE 0

Free PE 0

Allocated PE 0

PV UUID 08dOWh-3dFQ-rQ00-VTGi-h9S2-PbaJ-aQKYSe

[root@hkpgsadg dev]# vgcreate -s 8M datavg /dev/xvdb1 /dev/xvdc1 /dev/xvde1

Volume group "datavg" successfully created

[root@hkpgsadg dev]# vgdisplay

--- Volume group ---

VG Name datavg

System ID

Format lvm2

Metadata Areas 3

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 3

Act PV 3

VG Size 899.98 GiB

PE Size 8.00 MiB

Total PE 115197

Alloc PE / Size 0 / 0

Free PE / Size 115197 / 899.98 GiB

VG UUID fINMY5-wBKS-QBKi-N6QI-ihMD-YaVb-j90u0x

--- Volume group ---

VG Name VolGroup

System ID

Format lvm2

Metadata Areas 2

Metadata Sequence No 5

VG Access read/write

VG Status resizable

MAX LV 0

Cur LV 2

Open LV 2

Max PV 0

Cur PV 2

Act PV 2

VG Size 119.50 GiB

PE Size 4.00 MiB

Total PE 30593

Alloc PE / Size 30593 / 119.50 GiB

Free PE / Size 0 / 0

VG UUID RdDeWr-qxlF-f1To-zNng-nxCV-e1Hd-3xVZfH

[root@hkpgsadg dev]# vgdisplay

--- Volume group ---

VG Name datavg

System ID

Format lvm2

Metadata Areas 3

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 3

Act PV 3

VG Size 899.98 GiB

PE Size 8.00 MiB

Total PE 115197

Alloc PE / Size 0 / 0

Free PE / Size 115197 / 899.98 GiB

VG UUID fINMY5-wBKS-QBKi-N6QI-ihMD-YaVb-j90u0x

--- Volume group ---

VG Name VolGroup

System ID

Format lvm2

Metadata Areas 2

Metadata Sequence No 5

VG Access read/write

VG Status resizable

MAX LV 0

Cur LV 2

Open LV 2

Max PV 0

Cur PV 2

Act PV 2

VG Size 119.50 GiB

PE Size 4.00 MiB

Total PE 30593

Alloc PE / Size 30593 / 119.50 GiB

Free PE / Size 0 / 0

VG UUID RdDeWr-qxlF-f1To-zNng-nxCV-e1Hd-3xVZfH

[root@hkpgsadg dev]# vgdisplay datavg

--- Volume group ---

VG Name datavg

System ID

Format lvm2

Metadata Areas 3

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 3

Act PV 3

VG Size 899.98 GiB

PE Size 8.00 MiB

Total PE 115197

Alloc PE / Size 0 / 0

Free PE / Size 115197 / 899.98 GiB

VG UUID fINMY5-wBKS-QBKi-N6QI-ihMD-YaVb-j90u0x

[root@hkpgsadg dev]# lvcreate -L 890G -n lvdata datavg

Logical volume "lvdata" created

[root@hkpgsadg dev]# lvdisplay

--- Logical volume ---

LV Path /dev/datavg/lvdata

LV Name lvdata

VG Name datavg

LV UUID yFWfNu-E1cr-px49-K9tH-Q0vU-BjfL-yt8hWh

LV Write Access read/write

LV Creation host, time hkpgsadg, 2016-04-13 16:45:21 +0800

LV Status available

# open 0

LV Size 890.00 GiB

Current LE 113920

Segments 3

Allocation inherit

Read ahead sectors auto

- currently set to 256

Block device 253:2

--- Logical volume ---

LV Path /dev/VolGroup/lv_root

LV Name lv_root

VG Name VolGroup

LV UUID 4bM3bz-gttp-qKgr-sd9L-d24M-RMEb-LO4L4h

LV Write Access read/write

LV Creation host, time localhost.localdomain, 2014-07-07 18:28:07 +0800

LV Status available

# open 1

LV Size 115.58 GiB

Current LE 29589

Segments 2

Allocation inherit

Read ahead sectors auto

- currently set to 256

Block device 253:0

--- Logical volume ---

LV Path /dev/VolGroup/lv_swap

LV Name lv_swap

VG Name VolGroup

LV UUID Ic6bZU-mt6c-b0LK-1n7F-62Kc-16V1-TkcXBU

LV Write Access read/write

LV Creation host, time localhost.localdomain, 2014-07-07 18:28:11 +0800

LV Status available

# open 1

LV Size 3.92 GiB

Current LE 1004

Segments 1

Allocation inherit

Read ahead sectors auto

- currently set to 256

Block device 253:1

[root@hkpgsadg dev]# mkfs.ext4 /dev/datavg/lvdata

mke2fs 1.41.12 (17-May-2010)

Filesystem label=

OS type: Linux

Block size=4096 (log=2)

Fragment size=4096 (log=2)

Stride=0 blocks, Stripe width=0 blocks

58327040 inodes, 233308160 blocks

11665408 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=4294967296

7120 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, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,

102400000, 214990848

Writing inode tables: done

Creating journal (32768 blocks): done

Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 32 mounts or

180 days, whichever comes first. Use tune2fs -c or -i to override.

[root@hkpgsadg dev]# mkdir /data

[root@hkpgsadg dev]# mount /dev/datavg/lvdata /data

[root@hkpgsadg dev]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

114G 4.5G 104G 5% /

tmpfs 62G 0 62G 0% /dev/shm

/dev/xvda1 485M 32M 428M 7% /boot

/dev/mapper/datavg-lvdata

877G 200M 832G 1% /data

[root@hkpgsadg dev]#

[root@hkpgsadg data]# pvcreate /dev/xvdf1

Physical volume "/dev/xvdf1" successfully created

[root@hkpgsadg data]# vgextend datavg /dev/xvdf1

Volume group "datavg" successfully extended

[root@hkpgsadg data]# lvdisplay

--- Logical volume ---

LV Path /dev/datavg/lvdata

LV Name lvdata

VG Name datavg

LV UUID yFWfNu-E1cr-px49-K9tH-Q0vU-BjfL-yt8hWh

LV Write Access read/write

LV Creation host, time hkpgsadg, 2016-04-13 16:45:21 +0800

LV Status available

# open 1

LV Size 890.00 GiB

Current LE 113920

Segments 3

Allocation inherit

Read ahead sectors auto

- currently set to 256

Block device 253:2

[root@hkpgsadg data]# vgdisplay

--- Volume group ---

VG Name datavg

System ID

Format lvm2

Metadata Areas 4

Metadata Sequence No 3

VG Access read/write

VG Status resizable

MAX LV 0

Cur LV 1

Open LV 1

Max PV 0

Cur PV 4

Act PV 4

VG Size 1.17 TiB

PE Size 8.00 MiB

Total PE 153596

Alloc PE / Size 113920 / 890.00 GiB

Free PE / Size 39676 / 309.97 GiB

VG UUID fINMY5-wBKS-QBKi-N6QI-ihMD-YaVb-j90u0x

[root@hkpgsadg data]# lvextend -L +100G /dev/datavg/lvdata

Extending logical volume lvdata to 990.00 GiB

Logical volume lvdata successfully resized

[root@hkpgsadg data]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

114G 4.5G 104G 5% /

tmpfs 62G 0 62G 0% /dev/shm

/dev/xvda1 485M 32M 428M 7% /boot

/dev/mapper/datavg-lvdata

877G 200M 832G 1% /data

[root@hkpgsadg data]# resize2fs /dev/datavg/lvdata

resize2fs 1.41.12 (17-May-2010)

Filesystem at /dev/datavg/lvdata is mounted on /data; on-line resizing required

old desc_blocks = 56, new_desc_blocks = 62

Performing an on-line resize of /dev/datavg/lvdata to 259522560 (4k) blocks.

The filesystem on /dev/datavg/lvdata is now 259522560 blocks long.

[root@hkpgsadg data]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

114G 4.5G 104G 5% /

tmpfs 62G 0 62G 0% /dev/shm

/dev/xvda1 485M 32M 428M 7% /boot

/dev/mapper/datavg-lvdata

975G 200M 925G 1% /data

Created by Tony.Tang[TangYun]2016.04

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Linux LVM檔案系統管理的建立和擴充套件

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