linux LVM配置2

   续上一章日志《linux LVM配置》，这章主要讲LVM空间的延伸与缩减

一、配置LVM空间增加

下面我们来测试下LVM分区的收缩、延伸

1、  使用fdisk来增加一个system ID 为8e的分区

2、  建立PV

3、  将PV加入到aixevg这个VG里面

4、  将VG加入到aixelv里面，增加空间

5、  用resize2fs将文件系统的容量确实增加

第一步：增加分区

[root@CentOS5 ~]# fdisk /dev/sdb
   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        1246    10008463+   5  Extended
/dev/sdb5               1         183     1469884+  8e  Linux LVM
/dev/sdb6             184         366     1469916   8e  Linux LVM
/dev/sdb7             367         549     1469916   8e  Linux LVM
/dev/sdb8             550         732     1469916   8e  Linux LVM
/dev/sdb9             733         915     1469916   8e  Linux LVM

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
[root@CentOS5 ~]#partprobe

先查看一下pvscan

[root@CentOS5 ~]# pvscan
  PV /dev/sdb5   VG aixevg   lvm2 [1.39 GB / 0    free]
  PV /dev/sdb6   VG aixevg   lvm2 [1.39 GB / 0    free]
  PV /dev/sdb7   VG aixevg   lvm2 [1.39 GB / 0    free]
  PV /dev/sdb8   VG aixevg   lvm2 [1.39 GB / 0    free]
  Total: 4 [5.56 GB] / in use: 4 [5.56 GB] / in no VG: 0 [0   ]

下面开始创建PV

[root@CentOS5 ~]#pvcreate /dev/sdb9
  Physical volume "/dev/sdb9" successfully created
[root@CentOS5 ~]#pvscan
  PV /dev/sdb5   VG aixevg          lvm2 [1.39 GB / 0    free]
  PV /dev/sdb6   VG aixevg          lvm2 [1.39 GB / 0    free]
  PV /dev/sdb7   VG aixevg          lvm2 [1.39 GB / 0    free]
  PV /dev/sdb8   VG aixevg          lvm2 [1.39 GB / 0    free]
  PV /dev/sdb9                      lvm2 [1.40 GB]
  Total: 5 [6.96 GB] / in use: 4 [5.56 GB] / in no VG: 1 [1.40 GB]

添加VG

[root@CentOS5 ~]#vgdisplay
  --- Volume group ---
  VG Name               aixevg
  System ID
  Format                lvm2

...（部分省略）...
  VG Size               5.56 GB
  PE Size               16.00 MB
  Total PE              356
  Alloc PE / Size       356 / 5.56 GB
  Free  PE / Size       0 / 0
...（部分省略）...
[root@CentOS5 ~]#vgextend aixevg /dev/sdb9
  Volume group "aixevg" successfully extended
[root@CentOS5 ~]#vgdisplay
  --- Volume group ---
  VG Name               aixevg
  System ID
  Format                lvm2
 ...（部分省略）...
  VG Size               6.95 GB
  PE Size               16.00 MB
  Total PE              445
  Alloc PE / Size       356 / 5.56 GB
  Free  PE / Size       89 / 1.39 GB
  ...（部分省略）...

从这里看到，我们扩展了VG后，Free多了89个PV

下面添加LV

[root@CentOS5 ~]#df -h /mnt/lvm/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/aixevg-aixelv
                      5.5G  140M  5.1G   3% /mnt/lvm
[root@CentOS5 ~]#lvresize -l +89 /dev/aixevg/aixelv
  Extending logical volume aixelv to 6.95 GB
  Logical volume aixelv successfully resized
[root@CentOS5 ~]#df -h /mnt/lvm/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/aixevg-aixelv
                      5.5G  140M  5.1G   3% /mnt/lvm

这里我们看到空间没有实际增加，大家在操作时可以先、后运行下lvdisplay命令，可以看到LV的空间已经增加了。下面我们用resize2fs命令那确定增加空间

Resize2fs命令格式

[root@CentOS5 ~]#resize2fs [-f] [device] [size]
-f：强制改变大小
Device：设备名称
Size：要增加或减少到的空间大小，如果不设置表示全部，它的单位有M、G、T

 

[root@CentOS5 ~]#resize2fs /dev/aixevg/aixelv
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/aixevg/aixelv is mounted on /mnt/lvm; on-line resizing required
Performing an on-line resize of /dev/aixevg/aixelv to 1822720 (4k) blocks.
The filesystem on /dev/aixevg/aixelv is now 1822720 blocks long.

[root@CentOS5 ~]#df -h /mnt/lvm/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/aixevg-aixelv
                      6.9G  141M  6.4G   3% /mnt/lvm

可以看到空间真的增加，到这来LVM的空间增加以告一段落，下面我们来试试LVM空间的减少

二、配置LVM空间减少

LVM减少空间的步骤只是把增加空间的步骤反做一遍就可以了

我演示一下减少/dev/sdb5这个分区

[root@CentOS5 ~]#df -h /mnt/lvm/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/aixevg-aixelv
                      6.9G  588M  6.0G   9% /mnt/lvm
[root@CentOS5 ~]#pvscan
  PV /dev/sdb5   VG aixevg   lvm2 [1.39 GB / 0    free]
  PV /dev/sdb6   VG aixevg   lvm2 [1.39 GB / 0    free]
  PV /dev/sdb7   VG aixevg   lvm2 [1.39 GB / 0    free]
  PV /dev/sdb8   VG aixevg   lvm2 [1.39 GB / 0    free]
  PV /dev/sdb9   VG aixevg   lvm2 [1.39 GB / 0    free]
  Total: 5 [6.95 GB] / in use: 5 [6.95 GB] / in no VG: 0 [0   ]

下面我们使用resize2fs来减少空间

这里我们算一下1.39X4X1024=5693M，这个值就是resize2fs要减少到的值

[root@CentOS5 ~]#umount /mnt/lvm/
[root@CentOS5 ~]#resize2fs /dev/aixevg/aixelv 5600M
resize2fs 1.39 (29-May-2006)
Please run 'e2fsck -f /dev/aixevg/aixelv' first.

提示我们使用：e2fsck -f /dev/aixevg/aixelv，扫描我们的分区

[root@CentOS5 ~]#e2fsck -f /dev/aixevg/aixelv
e2fsck 1.39 (29-May-2006)
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/aixevg/aixelv: 12062/908544 files (0.1% non-contiguous), 179023/1822720 blocks
[root@CentOS5 ~]#resize2fs /dev/aixevg/aixelv 5600M
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/aixevg/aixelv to 1433600 (4k) blocks.
The filesystem on /dev/aixevg/aixelv is now 1433600 blocks long.

[root@CentOS5 ~]#mount /dev/aixevg/aixelv /mnt/lvm/
[root@CentOS5 ~]#df -h /mnt/lvm/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/aixevg-aixelv
                      5.4G  587M  4.6G  12% /mnt/lvm

看到了吧，实际空间已经减小了，我们下面改变LV的大小

看看/dev/sdb5有多少个PV

[root@CentOS5 ~]#pvdisplay
  --- Physical volume ---
  PV Name               /dev/sdb5
  VG Name               aixevg
  PV Size               1.40 GB / not usable 11.43 MB
  Allocatable           yes (but full)
  PE Size (KByte)       16384
  Total PE              89
  Free PE               0
  Allocated PE          89
  PV UUID               dR35q4-Y7ma-EVqe-Ggxw-0mVX-6xjF-NZRDcX

上面看到/dev/sdb5有89个PV

[root@CentOS5 ~]#lvresize -l -89 /dev/aixevg/aixelv
  WARNING: Reducing active and open logical volume to 5.56 GB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce aixelv? [y/n]: y
  Reducing logical volume aixelv to 5.56 GB
  Logical volume aixelv successfully resized
[root@CentOS5 ~]#pvdisplay
  --- Physical volume ---
  PV Name               /dev/sdb5
  VG Name               aixevg
  PV Size               1.40 GB / not usable 11.43 MB
  Allocatable           yes (but full)
  PE Size (KByte)       16384
  Total PE              89
  Free PE               0
  Allocated PE          89
  PV UUID               dR35q4-Y7ma-EVqe-Ggxw-0mVX-6xjF-NZRDcX
....（部分省略）...
  PV Name               /dev/sdb9
  VG Name               aixevg
  PV Size               1.40 GB / not usable 11.46 MB
  Allocatable           yes
  PE Size (KByte)       16384
  Total PE              89
  Free PE               89
  Allocated PE          0
  PV UUID               8uWMkf-bIOE-ilG8-zEz1-EvN0-WQW2-YOUQdE

说明在/dev/sdb9上有空余的89个PV，也就是我们减少的那89个PV，但是我们要减少的/dev/sdb5这个分区，所以我们要转换一下

[root@CentOS5 ~]#pvmove /dev/sdb5 /dev/sdb9
  /dev/sdb5: Moved: 100.0%

现在在查看一次PV

[root@CentOS5 ~]#pvdisplay
  --- Physical volume ---
  PV Name               /dev/sdb5
  VG Name               aixevg
  PV Size               1.40 GB / not usable 11.43 MB
  Allocatable           yes
  PE Size (KByte)       16384
  Total PE              89
  Free PE               89
  Allocated PE          0
  PV UUID               dR35q4-Y7ma-EVqe-Ggxw-0mVX-6xjF-NZRDcX
...（部分省略）...
  --- Physical volume ---
  PV Name               /dev/sdb9
  VG Name               aixevg
  PV Size               1.40 GB / not usable 11.46 MB
  Allocatable           yes (but full)
  PE Size (KByte)       16384
  Total PE              89
  Free PE               0
  Allocated PE          89
  PV UUID               8uWMkf-bIOE-ilG8-zEz1-EvN0-WQW2-YOUQdE

接下来在VG里面移除/dev/sdb5

[root@CentOS5 ~]#vgreduce aixevg /dev/sdb5
  Removed "/dev/sdb5" from volume group "aixevg"
[root@CentOS5 ~]#pvscan
  PV /dev/sdb6   VG aixevg          lvm2 [1.39 GB / 0    free]
  PV /dev/sdb7   VG aixevg          lvm2 [1.39 GB / 0    free]
  PV /dev/sdb8   VG aixevg          lvm2 [1.39 GB / 0    free]
  PV /dev/sdb9   VG aixevg          lvm2 [1.39 GB / 0    free]
  PV /dev/sdb5                      lvm2 [1.40 GB]
  Total: 5 [6.96 GB] / in use: 4 [5.56 GB] / in no VG: 1 [1.40 GB]

到这里LVM的增、减空间基本告一段落了，以后我会继续更新LVM的快照，敬请期待