环境介绍:

  • VMware 5.5
  • CentOS 6.3 64-bit
  • / 根分区为 LVM
  • 原磁盘大小 40GB
  • 扩容后磁盘大小: 50GB

查看原来的磁盘文件系统空间状态, 根分区已经 100% 爆了!

[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root
38G 38G 0 100% /
tmpfs 246M 0 246M 0% /dev/shm
/dev/sda1 485M 32M 428M 7% /boot

在 VMware 中对原磁盘扩容到 50GB, 查看磁盘 sda 已经扩展到 50GB
安全起见,在扩容前,建议对数据进行备份。

[root@localhost ~]# fdisk /dev/sda -l
Disk /dev/sda: 53.7 GB, 53687091200 bytes
255 heads, 63 sectors/track, 6527 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00026a39
Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 64 5222 41430016 8e Linux LVM

在本文的例子中,磁盘 /dev/sda 已经扩展至 53.7 GB 而且当前只有两个主分区,所以我们后面就直接创建主分区 sda3 来帮助扩容。

查看 PV, VG, LV 状态,大小还没有变化

[root@localhost ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 VolGroup lvm2 a-- 39.51g 0
[root@localhost ~]# vgs
/etc/lvm/archive/.lvm_localhost.localdomain_18508_1413645104: write error failed: No space left on device
Volume group "VolGroup" metadata archive failed.
/etc/lvm/backup/VolGroup.tmp: write error failed: No space left on device
Backup of volume group VolGroup metadata failed.
VG #PV #LV #SN Attr VSize VFree
VolGroup 1 2 0 wz--n- 39.51g 0
[root@localhost ~]# lvs
LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert
lv_root VolGroup -wi-ao-- 38.54g
lv_swap VolGroup -wi-ao-- 992.00m

接下来我们需要将扩展出未曾使用的 10GB 空间创建一个新的主分区 sda3 来给逻辑卷扩容用。

[root@localhost ~]# fdisk /dev/sda
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): m
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition's system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 3
First cylinder (5222-6527, default 5222):
Using default value 5222
Last cylinder, +cylinders or +size{K,M,G} (5222-6527, default 6527):
Using default value 6527

然后修改分区类型为 8e 并写入分区表保存

Command (m for help): t
Partition number (1-4): 3
Hex code (type L to list codes): 8e
Changed system type of partition 3 to 8e (Linux LVM)
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.

重新扫描磁盘检查分区情况

[root@localhost ~]# partx -v -a /dev/sda
device /dev/sda: start 0 size 104857600
gpt: 0 slices
dos: 4 slices
# 1: 2048- 1026047 ( 1024000 sectors, 524 MB)
# 2: 1026048- 83886079 ( 82860032 sectors, 42424 MB)
# 3: 83886080-104856254 ( 20970175 sectors, 10736 MB)
# 4: 0- -1 ( 0 sectors, 0 MB)
BLKPG: Device or resource busy
error adding partition 1
BLKPG: Device or resource busy
error adding partition 2
added partition 3

分区 1/2 的报错可以忽略,我们需要看到的是分区 3 已经添加成功,如果看不到分区 3 或者添加失败需要重启使之生效。

创建新的 PV

[root@localhost ~]# pvcreate /dev/sda3
Writing physical volume data to disk "/dev/sda3"
Physical volume "/dev/sda3" successfully created

找到当前系统所使用的卷组名

[root@localhost ~]# vgdisplay
--- Volume group ---
VG Name VolGroup
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 39.51 GiB
PE Size 4.00 MiB
Total PE 10114
Alloc PE / Size 10114 / 39.51 GiB
Free PE / Size 0 / 0
VG UUID 2JrSeG-4Is7-ocIQ-zVrN-eha1-gYJQ-L1UnPn
/etc/lvm/archive/.lvm_localhost.localdomain_15862_675165963: write error failed: No space left on device
Volume group "VolGroup" metadata archive failed.
/etc/lvm/backup/VolGroup.tmp: write error failed: No space left on device
Backup of volume group VolGroup metadata failed.

VolGroup 就是它了!

接下来 vgextend 扩容VG:

[root@localhost ~]# vgextend VolGroup /dev/sda3
/etc/lvm/archive/.lvm_localhost.localdomain_17322_173527374: write error failed: No space left on device
Volume group "VolGroup" metadata archive failed.
Internal error: Attempt to unlock unlocked VG #orphans.

结果因为剩余空间为零扩容失败,囧, 删除掉一些文件再试。

[root@localhost ~]# vgextend VolGroup /dev/sda3
Volume group "VolGroup" successfully extended

pvscan 来查看 PV 空间使用情况来决定谁给谁加以及加多少空间。

[root@localhost ~]# pvscan
PV /dev/sda2 VG VolGroup lvm2 [39.51 GiB / 0 free]
PV /dev/sda3 VG VolGroup lvm2 [10.00 GiB / 10.00 GiB free]
Total: 2 [49.50 GiB] / in use: 2 [49.50 GiB] / in no VG: 0 [0 ]

在本文例子中我们需要增加 / 根分区的空间,用 df 命令来查看根分区所挂载的逻辑卷。

[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root
38G 8.3G 28G 23% /
tmpfs 246M 0 246M 0% /dev/shm
/dev/sda1 485M 32M 428M 7% /boot

所以我们可以看到 / 根分区是挂载在 VolGroup-lv_root 卷组下面的 root 逻辑卷

扩容 root 逻辑卷

[root@localhost ~]# lvextend -L+10G /dev/mapper/VolGroup-lv_root /dev/sda3
Extending logical volume lv_root to 48.54 GiB
Insufficient free space: 2560 extents needed, but only 2559 available
[root@localhost ~]# lvextend -L+9.99G /dev/mapper/VolGroup-lv_root /dev/sda3
Rounding size to boundary between physical extents: 9.99 GiB
Extending logical volume lv_root to 48.53 GiB
Logical volume lv_root successfully resized

文件系统扩容:

[root@localhost ~]# resize2fs /dev/mapper/VolGroup-lv_root
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/VolGroup-lv_root is mounted on /; on-line resizing required
old desc_blocks = 3, new_desc_blocks = 4
Performing an on-line resize of /dev/mapper/VolGroup-lv_root to 12722176 (4k) blocks.
The filesystem on /dev/mapper/VolGroup-lv_root is now 12722176 blocks long.

扩容完毕!

[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root
48G 8.4G 37G 19% /
tmpfs 246M 0 246M 0% /dev/shm
/dev/sda1 485M 32M 428M 7% /boot