CentOS根分区扩容方法

4533

                      操作环境：
[iyunv@linux ~]# uname -a
Linux linux 2.6.32-358.18.1.el6.x86_64#1 SMP Wed Aug 28 17:19:38 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
现状分析：
系统有两个硬盘，第一个硬盘107G,“/”分区空间当时分区时只给了7.7G过小，空间马上占完。现在系统有第二个硬盘sdb大小为16GB，希望把sdb的所有空间加入到“/”分区中，是其空间容量从7.7GB变成7.7GB+16GB（约2.4GB）。（当然如果这里只有一个硬盘sda,有很多空间尚未使用可以进行同样的操作）
操作步骤如下：
第一步、查看本机现有分区情况
[iyunv@linux ~]# df -h
文件系统容量已用可用已用%% 挂载点
/dev/mapper/VolGroup-lv_root
                    7.7G  7.1G 155M  98% /
tmpfs                3.9G  296K 3.9G  1% /dev/shm
/dev/sda1            485M  64M 396M  14% /boot
/dev/sda3              83G  350M  79G  1% /media
第二步、查看本机的磁盘情况
[iyunv@linux ~]# fdisk -l


Disk /dev/sda: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x000dc0ad


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        2089  16264192  8e  Linux LVM
/dev/sda3            2090      13054  88076362+  83  Linux


Disk /dev/mapper/VolGroup-lv_root: 8325 MB,8325693440 bytes
255 heads, 63 sectors/track, 1012 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000




Disk /dev/mapper/VolGroup-lv_swap: 8325 MB,8325693440 bytes
255 heads, 63 sectors/track, 1012 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000
注意：此时还没有在EXSI5.0中添加第二块硬盘
[iyunv@linux ~]#
第三步、添加第二块硬盘


查看此时系统磁盘情况
root@linux ~]# fdisk -l


Disk /dev/sda: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x000dc0ad


Device Boot      Start        End      Blocks  Id  System
/dev/sda1  *          1          64      512000  83  Linux
Partition 1 does not end on cylinderboundary.
/dev/sda2              64        2089  16264192  8e  Linux LVM
/dev/sda3            2090      13054  88076362+  83  Linux


Disk /dev/sdb: 17.2 GB, 17179869184 bytes
255 heads, 63 sectors/track, 2088 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000




Disk /dev/mapper/VolGroup-lv_root: 8325 MB,8325693440 bytes
255 heads, 63 sectors/track, 1012 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000




Disk /dev/mapper/VolGroup-lv_swap: 8325 MB,8325693440 bytes
255 heads, 63 sectors/track, 1012 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000


可以看到我们新添加的硬盘sdb


[iyunv@linux ~]#
第四步、对第二块硬盘sdb进行分区


[iyunv@linux ~]# fdisk /dev/sdb
Device contains neither a valid DOSpartition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with diskidentifier 0xfa4abbdc.
Changes will remain in memory only, untilyou decide to write them.
After that, of course, the previous contentwon't be recoverable.


Warning: invalid flag 0x0000 of partitiontable 4 will be corrected by w(rite)


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 compatibilityflag
d  delete a partition
l  list known partition types
m  print this menu
n  add a new partition
o  create a new empty DOSpartition table
p  print the partition table
q  quit without saving changes
s  create a new empty Sundisklabel
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 (expertsonly)


Command (m for help): n
Command action
e  extended
p  primary partition (1-4)
p
Partition number (1-4): 4
First cylinder (1-2088, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G}(1-2088, default 2088):
Using default value 2088


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


Calling ioctl() to re-read partition table.
Syncing disks.


说明：上面操作对sdb硬盘进行了分区操作，设为sdb4分区了（当然上面建立的主分区可以为1-4中的任意一个，我这里选择的4）。


第五步、对新建立的sdb4分区进行格式


[iyunv@linux ~]# mkfs.ext4 /dev/sdb4
mke2fs 1.41.12 (17-May-2010)
文件系统标签=
操作系统:Linux
块大小=4096 (log=2)
分块大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1048576 inodes, 4192957 blocks
209647 blocks (5.00%) reserved for thesuper user
第一个数据块=0
Maximum filesystem blocks=4294967296
128 block groups
32768 blocks per group, 32768 fragments pergroup
8192 inodes per group
Superblock backups stored on blocks:
      32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
      4096000


正在写入inode表: 完成
Creating journal (32768 blocks): 完成
Writing superblocks and filesystemaccounting information: done完成


This filesystem will be automaticallychecked every 20 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.


说明：将sdb4分区格式化为ext4格式，因为CentOS安装是系统的格式ext4，所以这里要注意一下。


第六步、格式后的sdb4分区添加为物理卷
[iyunv@linux ~]# pvcreate /dev/sdb4
Physical volume "/dev/sdb4" successfully created

第七步、查看当前系统的物理卷（PV）情况


[iyunv@linux ~]# pvdisplay
---Physical volume ---
PVName /dev/sda2
VGName VolGroup
PVSize 15.51 GiB / not usable3.00 MiB
Allocatable yes (butfull)
PESize 4.00 MiB
Total PE 3970
Free PE 0
Allocated PE 3970
PVUUID Up77sG-sNKf-Ja0k-crBf-N0wz-a5hy-T6sVFh


"/dev/sdb4" is a new physical volume of "15.99 GiB"
---NEW Physical volume ---
PVName /dev/sdb4
VGName
PVSize 15.99 GiB
Allocatable NO
PESize 0
Total PE 0
Free PE 0
Allocated PE 0
PVUUID Gqnw7N-HooX-S2Nz-1NIZ-YpOe-g0jo-grG1rQ
说明：可以看到添加的新物理卷sdb4，大小都符合我们添加时的设置




第八步、查看当前卷组情况
[iyunv@linux ~]# vgdisplay
---Volume group ---
VGName VolGroup
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VGAccess read/write
VGStatus resizable
MAXLV 0
CurLV 2
Open LV 2
MaxPV 0
CurPV 1
ActPV 1
VGSize 15.51 GiB
PESize 4.00 MiB
Total PE 3970
Alloc PE / Size 3970 / 15.51GiB
Free PE / Size 0 / 0
VGUUID PPrifh-glzl-nnxX-YkBm-xJ1s-rgnw-d1WsJd


第九步、将分区sdb4转换为扩展分区


[iyunv@linux ~]# vgextend VolGroup/dev/sdb4
Volume group "VolGroup" successfully extended


第十步、查看当前的逻辑卷


[iyunv@linux ~]# lvdisplay
---Logical volume ---
LVPath /dev/VolGroup/lv_root
LVName lv_root
VGName VolGroup
LVUUID dCIsej-0NWX-bVFe-bT6L-c4eY-oy4G-9lNBOC
LVWrite Access read/write
LVCreation host, time ,
LVStatus available
#open 1
LVSize 7.75 GiB
Current LE 1985
Segments 1
Allocation inherit
Read ahead sectors auto
-currently set to 256
Block device 253:0


---Logical volume ---
LVPath /dev/VolGroup/lv_swap
LVName lv_swap
VGName VolGroup
LVUUID K5bxJo-2SmM-6NCU-mBJP-Qzp1-ZODH-nbLK0k
LVWrite Access read/write
LVCreation host, time ,
LVStatus available
#open 1
LVSize 7.75 GiB
Current LE 1985
Segments 1
Allocation inherit
Read ahead sectors auto
-currently set to 256
Block device 253:1


说明：这里可以看到“/”根分区的路径名称为：/dev/VolGroup/lv_root


第十一步、查看扩展后的卷组情况
[iyunv@linux ~]# vgdisplay
---Volume group ---
VGName VolGroup
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 4
VGAccess read/write
VGStatus resizable
MAXLV 0
CurLV 2
Open LV 2
MaxPV 0
CurPV 2
ActPV 2
VGSize 31.50 GiB
PESize 4.00 MiB
Total PE 8064
Alloc PE / Size 3970 / 15.51GiB
Free PE / Size 4094 / 15.99 GiB
VGUUID PPrifh-glzl-nnxX-YkBm-xJ1s-rgnw-d1WsJd
说明：扩展后的卷子情况，可以看出大小增加了16GB（与第八步中的对比）


第十二步、将新增的逻辑卷全部扩展到“/”分区中


[iyunv@linux ~]# lvextend -L +15.99G/dev/VolGroup/lv_root
Rounding size to boundary between physical extents: 15.99 GiB
Extending logical volume lv_root to 23.75 GiB
Logical volume lv_root successfully resized


说明：这里sdb4总共有16G，所以把16BG全部添加给根分区。


第十三步、查看“/”根分区格式，并重新刷新根分区的大小
[iyunv@linux ~]# e2fsck -f/dev/VolGroup/lv_root
e2fsck 1.41.12 (17-May-2010)
/dev/VolGroup/lv_root is mounted.
e2fsck: 无法继续, 中止.


[iyunv@linux ~]# resize2fs /dev/VolGroup/lv_root
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/VolGroup/lv_root ismounted on /; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 2
Performing an on-line resize of/dev/VolGroup/lv_root to 6224896 (4k) blocks.
The filesystem on /dev/VolGroup/lv_root isnow 6224896 blocks long.
说明：命令resize2fs即刷新根分区“/dev/VolGroup/lv_root”的容量。


第十三步、查看刷新后根分区的大小


[iyunv@linux ~]# df -h
文件系统容量已用可用已用%% 挂载点
/dev/mapper/VolGroup-lv_root
24G 7.1G 16G 32% /
tmpfs 3.9G 144K 3.9G 1% /dev/shm
/dev/sda3 83G 350M 79G 1% /media/Lucene


说明：可以看到根分区的大小有7.7G变成了24G，重启一下系统再来看情况。此时就可以继续安装软件了，不会提示空间不足了。