測試環境：RHEL5.3；硬碟8G,1000M一個分區分成6個
一、創建邏輯卷的步驟：
1）通過pvcreate命令將linux分區處理成物理卷（PV)；
2）通過vgcreate命令將創建好的物理卷處理成卷組（Vg)；
3）通過lvcreate命令將卷組分成若干個邏輯卷（Lv)；
之後我們可以對邏輯卷進行格式化,掛載,刪除等操作,我們可以動態的調整邏輯卷的大小,並且該操作不會影響我們在邏輯卷（Lv)上的數據.
二、物理卷創建管理操作：
1）pvcreate創建物理卷：( 把普通Linux分區變成物理卷）
格式：pvcreate /dev/sdb{1,2,3...}
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[root@station1 ~]# [root@station1 ~]# pvcreate /dev/sdb{1,2,3,5,6,7}
Physical volume "/dev/sdb3" successfully created
Physical volume "/dev/sdb5" successfully created
Physical volume "/dev/sdb6" successfully created
Physical volume "/dev/sdb7" successfully created
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2）pvscan查看物理卷信息：會顯示所有物理卷的情況.
格式：pvscan
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[root@station1 ~]# pvscan
PV /dev/sdb1 lvm2 [964.81 MB]
PV /dev/sdb2 lvm2 [964.84 MB]
PV /dev/sdb3 lvm2 [964.84 MB]
PV /dev/sdb5 lvm2 [964.81 MB]
PV /dev/sdb6 lvm2 [964.81 MB]
PV /dev/sdb7 lvm2 [964.81 MB]
Total: 6 [5.65 GB] / in use: 0 [0 ] / in no VG: 6 [5.65 GB]
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3）pvdisplay查看各個物理卷的詳細參數：
格式：pvdisplay [/dev/sdb{1,2,3...}] 不跟參數則顯示所有的物理卷信息
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[root@station1 ~]# pvdisplay /dev/sdb1
"/dev/sdb1" is a new physical volume of "964.81 MB"
--- NEW Physical volume ---
PV Name /dev/sdb1
VG Name
PV Size 964.81 MB
Allocatable NO
PE Size (KByte) 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID FKaYKk-d46E-KHCQ-WRnn-jUUE-Cd1d-mM8mPN
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4）pvremove刪除物理卷：當物理卷里的擴展快沒有被使用時可以刪除.
格式：pvremove /dev/sdb5
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[root@station1 ~]# pvscan
PV /dev/sdb7 VG vg1 lvm2 [960.00 MB / 960.00 MB free]
PV /dev/sdb1 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
PV /dev/sdb2 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
PV /dev/sdb3 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
PV /dev/sdb5 lvm2 [964.81 MB]
PV /dev/sdb6 lvm2 [964.81 MB]
Total: 6 [5.65 GB] / in use: 4 [3.76 GB] / in no VG: 2 [1.88 GB]
[root@station1 ~]# pvremove /dev/sdb5
Labels on physical volume "/dev/sdb5" successfully wiped
[root@station1 ~]# pvscan
PV /dev/sdb7 VG vg1 lvm2 [960.00 MB / 960.00 MB free]
PV /dev/sdb1 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
PV /dev/sdb2 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
PV /dev/sdb3 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
PV /dev/sdb6 lvm2 [964.81 MB]
Total: 5 [4.70 GB] / in use: 4 [3.76 GB] / in no VG: 1 [964.81 MB]
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三、卷組的創建管理：
1）vgcreate創建卷組：
格式：vgcreate [-s <8M|16M|...>] vg0 /dev/sdb{1,2,3...}
-s：指定擴展塊（PE）的大小,默認為4MB；（相當與磁碟上的簇,擴展邏輯卷的基本單位. 後面的值可以是8M 16M 32M 64M .....最多65532個擴展塊.
vg0：新創建的卷組的名字.
/dev/sdb{1,2,3...}：需要的物理卷可以寫多個；
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[root@station1 ~]# vgcreate vg0 /dev/sdb{1,2,3}
Volume group "vg0" successfully created
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2）vgdisplay查看各個卷組的詳細參數：
格式：vgdisplay /dev/vg0
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[root@station1 ~]# vgdisplay /dev/vg0
--- Volume group ---
VG Name vg0
System ID
Format lvm2
Metadata Areas 3
Metadata Sequence No 1
VG Access read/write
VG Status resizable
Cur PV 3
Act PV 3
VG Size 2.82 GB
PE Size 4.00 MB //擴展快大小 默認4MB
Total PE 723
Alloc PE / Size 0 / 0
Free PE / Size 723 / 2.82 GB
VG UUID w4q8ET-UBLY-rHwg-2ZVv-NOw4-dd1e-1ABr2f
[root@station1 ~]# vgcreate -s 16M vg1 /dev/sdb{5,6,7}
Volume group "vg1" successfully created
[root@station1 ~]# vgdisplay /dev/vg1
--- Volume group ---
VG Name vg1
System ID
Format lvm2
Metadata Areas 3
Metadata Sequence No 1
VG Access read/write
VG Status resizable
Cur PV 3
Act PV 3
VG Size 2.81 GB
PE Size 16.00 MB //指定擴展塊大小為16MB
Total PE 180
Alloc PE / Size 0 / 0
Free PE / Size 180 / 2.81 GB
VG UUID x97eh2-JYxW-4Ygh-5axx-TquS-0vxR-YdFyJ1
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3）vgscan查看卷組的信息：
格式：vgsacn
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[root@station1 ~]# vgscan
Found volume group "vg1" using metadata type lvm2
Found volume group "vg0" using metadata type lvm2
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4）vgreduce縮小卷組：把物理卷重卷組中刪除.
格式：vgreduce vg0 /dev/sdb3
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[root@station1 ~]# vgreduce vg0 /dev/sdb3
Removed "/dev/sdb3" from volume group "vg0"
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4）vgextend擴展卷組：把某個物理卷添加到卷組中.
格式：vgextend vg0 /dev/sdb2 將物理卷/dev/sdb2添加到vg0卷組
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[root@station1 ~]# vgextend vg0 /dev/sdb3
Volume group "vg0" successfully extended
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5）vgremove刪除卷組：
格式：vgremove /dev/vg1
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[root@station1 ~]# pvscan
PV /dev/sdb7 VG vg1 lvm2 [960.00 MB / 960.00 MB free]
PV /dev/sdb5 VG vg1 lvm2 [960.00 MB / 960.00 MB free]
PV /dev/sdb6 VG vg1 lvm2 [960.00 MB / 960.00 MB free]
PV /dev/sdb1 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
PV /dev/sdb2 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
PV /dev/sdb3 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
Total: 6 [5.64 GB] / in use: 6 [5.64 GB] / in no VG: 0 [0 ]
[root@station1 ~]# vgremove /dev/vg1
Volume group "vg1" successfully removed
[root@station1 ~]# pvscan
PV /dev/sdb1 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
PV /dev/sdb2 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
PV /dev/sdb3 VG vg0 lvm2 [964.00 MB / 964.00 MB free]
PV /dev/sdb5 lvm2 [964.81 MB]
PV /dev/sdb6 lvm2 [964.81 MB]
PV /dev/sdb7 lvm2 [964.81 MB]
Total: 6 [5.65 GB] / in use: 3 [2.82 GB] / in no VG: 3 [2.83 GB]
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四、邏輯卷的創建及管理：
1）lvcreate創建邏輯卷命令：
格式1：lvcreate -L 512M -n data vg0
-L 512M：設置邏輯卷的大小為512M.
-n data：設置邏輯卷的名字為data ；表示法：/dev/卷組名/data
vg0 ：設置是有那個卷組生成的邏輯卷.
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[root@station1 ~]# lvcreate -L 1000M -n data vg0
Logical volume "data" created
//創建一個容量為1000MB的邏輯卷data
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格式2：lvcreate -l 32 -n data vg0
-l 32：生成的邏輯卷使用32個擴展塊,邏輯卷大小=32*PE（默認4M）則為128M
-n data：邏輯卷的名字；
vg0 ：設置是有那個卷組生成的邏輯卷.
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[root@station1 ~]# lvcreate -l 32 -n data128 vg0
Logical volume "data128" created
//創建一個32個擴展塊,容量為32*4=128MB的邏輯卷data128
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2）格式化邏輯卷：
mkfs.ext3 /dev/vg0/data mke2fs -j /dev/vg0/data
3）lvsacn查看邏輯卷的信息：
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[root@station1 ~]# lvscan
ACTIVE '/dev/vg0/data' [1000.00 MB] inherit
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4）lvdisplay查看邏輯卷的具體參數：
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[root@station1 ~]# lvdisplay /dev/vg0/data
--- Logical volume ---
LV Name /dev/vg0/data
VG Name vg0
LV UUID 9Od1nq-cHmY-MlrL-vgXW-7Kam-pAfU-Qc8mal
LV Write Access read/write
LV Status available
# open 0
LV Size 1000.00 MB
Current LE 250
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
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3）增大邏輯卷大小：
lvextend命令：增大邏輯卷大小
格式：lvextend -L 100M /dev/vg0/data
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[root@station1 ~]# lvextend -L 1000M /dev/vg0/data
Extending logical volume data to 1.95 GB
Logical volume data successfully resized
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resize2fs /dev/vg0/data 使上面增加的立即生效.
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[root@station1 ~]# resize2fs /dev/vg0/data
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/vg0/data to 512000 (4k) blocks.
The filesystem on /dev/vg0/data is now 512000 blocks long.
[root@station1 ~]# lvscan
ACTIVE '/dev/vg0/data' [1.95 GB] inherit
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4）減少邏輯卷大小：
lvreduce命令：減少邏輯卷大小
格式：Lvreduce -L -100M /dev/vg0/data
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[root@station1 ~]# lvreduce -L -1000M /dev/vg0/data
WARNING: Reducing active logical volume to 1000.00 MB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce data? [y/n]: y
Reducing logical volume data to 1000.00 MB
Logical volume data successfully resized
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resize2fs /dev/vg0/data 使上面增加的立即生效.
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[root@station1 ~]# resize2fs /dev/vg0/data
resize2fs 1.39 (29-May-2006)
resize2fs: Bad magic number in super-block while trying to open /dev/vg0/data
Couldn't find valid filesystem superblock.
[root@station1 ~]# lvscan
ACTIVE '/dev/vg0/data' [1000.00 MB] inherit
ACTIVE '/dev/vg0/data128' [128.00 MB] inherit
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5)lvremove刪除邏輯卷：
格式：lvremove /dev/卷組名/邏輯卷名
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[root@station1 ~]# lvremove /dev/vg0/data128
Do you really want to remove active logical volume "data128"? [y/n]: y
Logical volume "data128" successfully removed
[root@station1 ~]# lvscan
ACTIVE '/dev/vg0/data' [1000.00 MB] inherit
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五、LVM的快照：
1）快照的創建：
Lvcreate -l 64 -s -n databackup /dev/vg0/data
-l 64：之前我們已經說過了這裡是 64個擴展塊,總容量=64*單擴展塊大小
-n databackup：生成的快照的名字.
/dev/vg0/data：源邏輯卷名字.
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[root@station1 ~]# lvscan
ACTIVE '/dev/vg0/data' [1000.00 MB] inherit
[root@station1 ~]# lvcreate -L 1000M -s -n databackup /dev/vg0/data
Logical volume "databackup" created
[root@station1 ~]# lvscan
ACTIVE Original '/dev/vg0/data' [1000.00 MB] inherit
ACTIVE Snapshot '/dev/vg0/databackup' [1000.00 MB] inherit
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2）快照的刪除：
lvremove /dev/vg0/databackup
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[root@station1 ~]# lvremove /dev/vg0/databackup
Do you really want to remove active logical volume "databackup"? [y/n]: y
Logical volume "databackup" successfully removed
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六、總結：
創建邏輯卷的順序：Linux分區---物理卷---卷組---邏輯卷
刪除邏輯卷的順序：邏輯卷---卷組----物理卷---Linux分區
