linux之lvm学习 (转载)

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本文通过在虚拟机上安装Linux系统并进行LVM实践操作，详细介绍了如何创建物理卷、卷组和逻辑卷，以及如何调整逻辑卷的大小。此外，还记录了解决过程中遇到的问题。

5月20号更新：

今天把我本子上的 vmware上重新整了下，虚拟一个Linux ，实地演练下LVM

1.装好linux系统，我给虚拟机开辟了一个 /dev/hda 硬盘，3G空间，为了实验LVM，我有给虚拟机添加了一块硬盘

/dev/hdb 2G 空间

注意： 我在虚拟机中装Linux的时候，遇到了系统找不到硬盘的情况，开始以为光盘有问题，在网上重新下载了ISO包，安装，问题依旧，最后才发现我这个版本的vmware 对硬盘支持的类型只能是 IDE 的，改了硬盘类型就OK了

2. 使用 fdisk -l 查看磁盘情况，可以看到 hdb 的类型是 linux

3. 将 hdb 从linux 改成 linux LVM,一定要使用 w 保存退出,再次查看已经是linux lvm了

fdisk /dev/hdb ->m -> t -> 3 -> 8e -> w

[root@xhu-vm ~]# fdisk -l

Disk /dev/hda: 3221 MB, 3221225472 bytes
255 heads, 63 sectors/track, 391 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1   *           1          13      104391   83  Linux
/dev/hda2              14         391     3036285   8e  Linux LVM

Disk /dev/hdb: 2147 MB, 2147483648 bytes
16 heads, 63 sectors/track, 4161 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hdb3               1        4161     2097112+  8e  Linux LVM

4.创建 PV
pvcreate /dev/hdb

查看创建好的pv

[root@xhu-vm ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/hda2
  VG Name               VolGroup00
  PV Size               2.88 GB / not usable 0  
  Allocatable           yes
  PE Size (KByte)       32768
  Total PE              92
  Free PE               1
  Allocated PE          91
  PV UUID               el1YY6-k7dU-V7mA-Uvyk-TNuH-Dnsm-yRBxDC
  
  --- NEW Physical volume ---
  PV Name               /dev/hdb
  VG Name              
  PV Size               2.00 GB
  Allocatable           NO
  PE Size (KByte)       0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               r1uwvi-NhI1-bVS5-qfZQ-GR8M-VNkX-UW0Ajr

5.创建卷组

[root@xhu-vm ~]# vgcreate VolGroup01 /dev/hdb
  Volume group "VolGroup01" successfully created

查看卷组

[root@xhu-vm ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/hdb
  VG Name               VolGroup01
  PV Size               2.00 GB / not usable 0  
  Allocatable           yes
  PE Size (KByte)       4096
  Total PE              511
  Free PE               511
  Allocated PE          0
  PV UUID               r1uwvi-NhI1-bVS5-qfZQ-GR8M-VNkX-UW0Ajr
  
  --- Physical volume ---
  PV Name               /dev/hda2
  VG Name               VolGroup00
  PV Size               2.88 GB / not usable 0  
  Allocatable           yes
  PE Size (KByte)       32768
  Total PE              92
  Free PE               1
  Allocated PE          91
  PV UUID               el1YY6-k7dU-V7mA-Uvyk-TNuH-Dnsm-yRBxDC

或者这么查看

[root@xhu-vm ~]# vgdisplay
  --- Volume group ---
  VG Name               VolGroup01
  System ID            
  Format                lvm2
  Metadata Areas        1
  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                1
  Act PV                1
  VG Size               2.00 GB
  PE Size               4.00 MB
  Total PE              511
  Alloc PE / Size       0 / 0  
  Free  PE / Size       511 / 2.00 GB
  VG UUID               bVxufu-AZWK-ifl2-e8OQ-AH7k-oMuR-Dkn5Cm
  
  --- Volume group ---
  VG Name               VolGroup00
  System ID            
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  3
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               2.88 GB
  PE Size               32.00 MB
  Total PE              92
  Alloc PE / Size       91 / 2.84 GB
  Free  PE / Size       1 / 32.00 MB
  VG UUID               jUbO2f-SWru-9BXD-Kp16-AGbp-0pQE-fw5YJ2

6. 激活卷组

[root@xhu-vm ~]# vgchange -a y VolGroup01
  0 logical volume(s) in volume group "VolGroup01" now active
[root@xhu-vm ~]#

7.创建逻辑卷(152M)

[root@xhu-vm ~]# lvcreate -L150  -nLogVol02  VolGroup01
  /dev/cdrom: open failed: Read-only file system
  Rounding up size to full physical extent 152.00 MB
  Logical volume "LogVol02" created
[root@xhu-vm ~]#

8.格式化文件系统 + mount 到 /data/wwwroot

[root@xhu-vm ~]# mkdir /data/wwwroot
[root@xhu-vm ~]# mkfs -V -t ext3 /dev/VolGroup01/LogVol02
mkfs version 2.12a (Dec 21 2004)
mkfs.ext3 /dev/VolGroup01/LogVol02
mke2fs 1.35 (28-Feb-2004)
max_blocks 159383552, rsv_groups = 19456, rsv_gdb = 256
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
38912 inodes, 155648 blocks
7782 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=67371008
19 block groups
8192 blocks per group, 8192 fragments per group
2048 inodes per group
Superblock backups stored on blocks:
        8193, 24577, 40961, 57345, 73729

Writing inode tables: done                           
inode.i_blocks = 3074, i_size = 67383296
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 39 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
[root@xhu-vm ~]# mount  /dev/VolGroup01/LogVol02 /data/wwwroot
[root@xhu-vm ~]#

9. 拷贝一个文件到 /data/wwwroot

[root@xhu-vm wwwroot]# df -k
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                       2418944   1464868    831196  64% /
/dev/hda1               101086      9028     86839  10% /boot
none                    128020         0    128020   0% /dev/shm
/dev/mapper/VolGroup01-LogVol02
                        150733     11554    131397   9% /data/wwwroot

注意： 我创建的 LogVol02 有152M，当你他的 mount点 /data/wwwroot 拷贝数据的时候，超过152M会报错，再次操作 /data/wwwroot 的时候会说 file system read only. 只要你增加了这个lv的容量就万事OK了，可见LVM的好处

10.增加这个LV增加容量100M

lvextend -L+100 /dev/VolGroup01/LogVol02

lvs 看看现在的容量

11.减少 LV的容量减少100M

    lvreduce -L-100 /dev/VolGroup01/LogVol02


12. 在 VolGroup01 继续建立一个LV LogVol03

lvcreate -L150 -nLogVol03 VolGroup01

参考：

Linux添加硬盘并分区格式化

Linux系统新加物理盘实现LVM管理

虚拟机环境中linux系统增加磁盘空间

linux之lvm学习

硬盘分区如何设定大小,如何规划,再好的规划也有出差错的时候,人算不如天算.
为了让我们脱离那可悲的分区与分区修改工具,请跟我来认识一下LVM-逻辑卷管理(logical volume manager).

首先先把基本术语定义讲一下:
LVM 是linux对磁盘分区进行管理的一种机制.LVM是建立在磁盘与分区之上的一个逻辑层,以提高磁盘管理的灵活性.
在LVM内有三个基本术语PV(Physical Volume 物理卷) VG(Volume Group 卷组) LV(Logical Volume 逻辑卷)
三者的关系为,先建立PV,根据PV组合或扩展形成VG,根据用户需求使用VG卷的总量去建立相应的LV卷(个人理解)
一.创建PV的命令与方法
1.查看磁盘分区情况:
[root@localhost /]# fdisk -l /dev/hdb

Disk /dev/hdb: 21.4 GB, 21474836480 bytes
15 heads, 63 sectors/track, 44384 cylinders
Units = cylinders of 945 * 512 = 483840 bytes

   Device Boot      Start         End      Blocks   Id System
/dev/hdb1               1       10000     4724968+ 83 Linux
/dev/hdb2           10001       20000     4725000   83 Linux
/dev/hdb3           20001       30000     4725000   83 Linux
/dev/hdb4           30001       44384     6796440   83 Linux
共计4个分区请大家看ID位置代码:83 system:linux,我们需要更改ID代码为8e 此为LVM卷分区标签
分区系统号更改方法如下:
[root@localhost /]# fdisk /dev/hdb
Command (m for help): t
Partition number (1-4): 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)
此时系统ID已经更改为LVM,我们再用FDISK命令查看一下磁盘情况
[root@localhost /]# fdisk -l /dev/hdb

Disk /dev/hdb: 21.4 GB, 21474836480 bytes
15 heads, 63 sectors/track, 44384 cylinders
Units = cylinders of 945 * 512 = 483840 bytes

   Device Boot      Start         End      Blocks   Id System
/dev/hdb1               1       10000     4724968+ 8e Linux LVM
/dev/hdb2           10001       20000     4725000   8e Linux LVM
SYStem类型:Linux LVM,此时我们可以创建PV了,我创建了二个PV,通过pvdisplay命令可以查看创建的PV卷的情况.
[root@localhost /]# pvcreate /dev/hdb1 /dev/hdb2
Physical volume "/dev/hdb1" successfully created
Physical volume "/dev/hdb2" successfully created
查看PV卷详细信息:
[root@localhost /]# pvdisplay
"/dev/hdb1" is a new physical volume of "4.51 GB"
--- NEW Physical volume ---
PV Name               /dev/hdb1
VG Name
PV Size               4.51 GB
Allocatable           NO
PE Size (KByte)       0
Total PE              0
Free PE               0
Allocated PE          0
PV UUID               gSv31K-01SU-1Vbm-HF26-MR5W-wgBw-1EeHb0

"/dev/hdb2" is a new physical volume of "4.51 GB"
--- NEW Physical volume ---
PV Name               /dev/hdb2
VG Name
PV Size               4.51 GB
Allocatable           NO
PE Size (KByte)       0
Total PE              0
Free PE               0
Allocated PE          0
PV UUID               ODEuTv-iMqs-Wzxq-HMyB-yUw2-Lnwn-5JdlSp
我们此时再回看查看一下磁盘分区的情况.
[root@localhost /]# fdisk -l /dev/hdb

Disk /dev/hdb: 21.4 GB, 21474836480 bytes
15 heads, 63 sectors/track, 44384 cylinders
Units = cylinders of 945 * 512 = 483840 bytes

   Device Boot      Start         End      Blocks   Id System
/dev/hdb1               1       10000     4724968+ 8e Linux LVM
/dev/hdb2           10001       20000     4725000   8e Linux LVM
/dev/hdb3           20001       30000     4725000   8e Linux LVM
/dev/hdb4           30001       44384     6796440   8e Linux LVM
PV创建完成,相应的命令如下:pvcreate (PV创建) pvdisplay(PV信息查看) pvremove(pv卷删除)
pvremove /dev/hdb1 (删除命令例)

参考：