Linux逻辑卷管理（LVM）详细教程-红联Linux系统门户

[i=s] 本帖最后由我爱敏敏于 2009-8-13 13:05 编辑 [/i]

测试环境：RHEL5.3；硬盘8G，1000M一个分区分成6个
一、创建逻辑卷的步骤：
1）通过pvcreate命令将linux分区处理成物理卷（PV)；
2）通过vgcreate命令将创建好的物理卷处理成卷组（Vg)；
3）通过lvcreate命令将卷组分成若干个逻辑卷（Lv)；
之后我们可以对逻辑卷进行格式化，挂载，删除等操作，我们可以动态的调整逻辑卷的大小，并且该操作不会影响我们在逻辑卷（Lv)上的数据。
二、物理卷创建管理操作：
1）pvcreate创建物理卷：( 把普通Linux分区变成物理卷）
格式：pvcreate /dev/sdb{1,2,3...}
--------------------------------------------------------------
[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
----------------------------------------------------------------
2）pvscan查看物理卷信息：会显示所有物理卷的情况。
格式：pvscan
----------------------------------------------------------------
[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]
----------------------------------------------------------------
3）pvdisplay查看各个物理卷的详细参数：
格式：pvdisplay [/dev/sdb{1,2,3...}] 不跟参数则显示所有的物理卷信息
----------------------------------------------------------------
[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
------------------------------------------------------------------------
4）pvremove删除物理卷：当物理卷里的扩展快没有被使用时可以删除。
格式：pvremove /dev/sdb5
------------------------------------------------------------
[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]
----------------------------------------------------------------
三、卷组的创建管理：
1）vgcreate创建卷组：
格式：vgcreate [-s <8M|16M|...>] vg0 /dev/sdb{1,2,3...}
-s：指定扩展块（PE）的大小，默认为4MB；（相当与磁盘上的簇，扩展逻辑卷的基本单位。后面的值可以是8M 16M 32M 64M .....最多65532个扩展块。
vg0：新创建的卷组的名字。
/dev/sdb{1,2,3...}：需要的物理卷可以写多个；
----------------------------------------------------------------
[root@station1 ~]# vgcreate vg0 /dev/sdb{1,2,3}
Volume group "vg0" successfully created
----------------------------------------------------------------
2）vgdisplay查看各个卷组的详细参数：
格式：vgdisplay /dev/vg0
----------------------------------------------------------------
[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 //扩展快大小默认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 //指定扩展块大小为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
----------------------------------------------------------------------
3）vgscan查看卷组的信息：
格式：vgsacn
----------------------------------------------------------------
[root@station1 ~]# vgscan
Found volume group "vg1" using metadata type lvm2
Found volume group "vg0" using metadata type lvm2
------------------------------------------------------------------
4）vgreduce缩小卷组：把物理卷重卷组中删除。
格式：vgreduce vg0 /dev/sdb3
--------------------------------------------------------------------
[root@station1 ~]# vgreduce vg0 /dev/sdb3
Removed "/dev/sdb3" from volume group "vg0"
--------------------------------------------------------------------
4）vgextend扩展卷组：把某个物理卷添加到卷组中。
格式：vgextend vg0 /dev/sdb2 将物理卷/dev/sdb2添加到vg0卷组
--------------------------------------------------------------------
[root@station1 ~]# vgextend vg0 /dev/sdb3
Volume group "vg0" successfully extended
--------------------------------------------------------------------
5）vgremove删除卷组：
格式：vgremove /dev/vg1
--------------------------------------------------------------------
[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]
--------------------------------------------------------------------
四、逻辑卷的创建及管理：
1）lvcreate创建逻辑卷命令：
格式1：lvcreate -L 512M -n data vg0
-L 512M：设置逻辑卷的大小为512M。
-n data：设置逻辑卷的名字为data ；表示法：/dev/卷组名/data
vg0 ：设置是有那个卷组生成的逻辑卷。
--------------------------------------------------------------------
[root@station1 ~]# lvcreate -L 1000M -n data vg0
Logical volume "data" created
//创建一个容量为1000MB的逻辑卷data
--------------------------------------------------------------------
格式2：lvcreate -l 32 -n data vg0
-l 32：生成的逻辑卷使用32个扩展块，逻辑卷大小=32*PE（默认4M）则为128M
-n data：逻辑卷的名字；
vg0 ：设置是有那个卷组生成的逻辑卷。
--------------------------------------------------------------------
[root@station1 ~]# lvcreate -l 32 -n data128 vg0
Logical volume "data128" created
//创建一个32个扩展块，容量为32*4=128MB的逻辑卷data128
--------------------------------------------------------------------
2）格式化逻辑卷：
mkfs.ext3 /dev/vg0/data mke2fs -j /dev/vg0/data
3）lvsacn查看逻辑卷的信息：
¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬--------------------------------------------------------------------
[root@station1 ~]# lvscan
ACTIVE '/dev/vg0/data' [1000.00 MB] inherit
--------------------------------------------------------------------
4）lvdisplay查看逻辑卷的具体参数：
--------------------------------------------------------------------
[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
--------------------------------------------------------------------
3）增大逻辑卷大小：
lvextend命令：增大逻辑卷大小
格式：lvextend -L +100M /dev/vg0/data
--------------------------------------------------------------------
[root@station1 ~]# lvextend -L +1000M /dev/vg0/data
Extending logical volume data to 1.95 GB
Logical volume data successfully resized
--------------------------------------------------------------------
resize2fs /dev/vg0/data 使上面增加的立即生效。
--------------------------------------------------------------------
[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
--------------------------------------------------------------------
4）减少逻辑卷大小：
lvreduce命令：减少逻辑卷大小
格式：Lvreduce -L -100M /dev/vg0/data
--------------------------------------------------------------------
[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
--------------------------------------------------------------------
resize2fs /dev/vg0/data 使上面增加的立即生效。
--------------------------------------------------------------------
[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
--------------------------------------------------------------------
5)lvremove删除逻辑卷：
格式：lvremove /dev/卷组名/逻辑卷名
--------------------------------------------------------------------
[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
--------------------------------------------------------------------
五、LVM的快照：
1）快照的创建：
Lvcreate -l 64 -s -n databackup /dev/vg0/data
-l 64：之前我们已经说过了这里是 64个扩展块，总容量=64*单扩展块大小
-n databackup：生成的快照的名字。
/dev/vg0/data：源逻辑卷名字。
------------------------------------------------------------------------
[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
------------------------------------------------------------------------
2）快照的删除：
lvremove /dev/vg0/databackup
------------------------------------------------------------------------
[root@station1 ~]# lvremove /dev/vg0/databackup
Do you really want to remove active logical volume "databackup"? [y/n]: y
Logical volume "databackup" successfully removed
------------------------------------------------------------------------
六、总结：
创建逻辑卷的顺序：Linux分区---物理卷---卷组---逻辑卷
删除逻辑卷的顺序：逻辑卷---卷组----物理卷---Linux分区

Linux逻辑卷管理（LVM）详细教程

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