CentOS 5 LVM 在线扩容根分区

说明：
Linux 2.6以上内核支持ext3的在线扩容

第一种情况：直接添加一个新硬盘
# df -h 看看现在硬盘的情况
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                      6.7G  5.2G  1.3G  81% /
/dev/sda1              99M   12M   82M  13% /boot
tmpfs                 633M     0  633M   0% /dev/shm
# fdisk -l 可以看到新添加的硬盘/dev/sdb
Disk /dev/sda: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          13      104391   83  Linux
/dev/sda2              14        1044     8281507+  8e  Linux LVM

Disk /dev/sdb: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdb doesn't contain a valid partition table
# lvm
lvm>vgdisplay 可以先看卷组是否还有剩余空间可以扩展，有的话直接扩展，没有或不够的话把新的硬盘添加进去
  --- 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               7.88 GB
  PE Size               32.00 MB
  Total PE              252
  Alloc PE / Size       252 / 7.88 GB
  Free  PE / Size       0 / 0  
  VG UUID               0U8dPB-UTJZ-Mdv5-eZJM-Xj7f-gR1M-63BcCh
lvm>pvcreate /dev/sdb  使用新的整个硬盘创建一个lvm物理卷
lvm>vgextend /dev/VolGroup00 /dev/sdb  把新的物理卷添加到卷组中
lvm>vgdisplay 可以看到已分配空间和剩余未分配空间 All PE / Size 和 Free PE / Size
 --- Volume group ---
  VG Name               VolGroup00
  System ID            
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  4
  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               15.84 GB
  PE Size               32.00 MB
  Total PE              507
  Alloc PE / Size       252 / 7.88 GB
  Free  PE / Size       255 / 7.97 GB
  VG UUID               0U8dPB-UTJZ-Mdv5-eZJM-Xj7f-gR1M-63BcCh
lvm>lvextend -L +7.9G /dev/VolGroup00/LogVol00 扩展逻辑卷大小
lvm>vgdisplay
lvm>pvdisplay
lvm>lvdisplay 可以看到已经添加了
 --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol00
  VG Name                VolGroup00
  LV UUID                QtNkTM-TeSo-WnZD-fSUr-6k1F-5aLX-zAIfSQ
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                14.78 GB
  Current LE             473
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0
  
  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol01
  VG Name                VolGroup00
  LV UUID                bhTEBX-t8XK-zGku-NCzx-eolz-Anvj-jUMUER
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                1.00 GB
  Current LE             32
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1
lvm>quit
# resize2fs -p /dev/VolGroup00/LogVol00  修改文件系统大小以实现扩充空间
# df -h

第二种情况：只添加一个新分区
# df -h 可以看到新添加的硬盘/dev/sdb1
# lvm
lvm>pvcreate /dev/sdb1  使用新的硬盘创建一个lvm物理卷
lvm>vgextend /dev/VolGroup00 /dev/sdb1
lvm>vgdisplay 可以看到已分配空间和剩余未分配空间 All PE / Size 和 Free PE / Size
lvm>lvextend -L +5G /dev/VolGroup00/LogVol00
lvm>vgdisplay
lvm>pvdisplay
lvm>lvdisplay
lvm>quit
# resize2fs -p /dev/VolGroup00/LogVol00  扩展
# df -h