Linux系统由于数据累计增长、前期存储规划不合理等诸多因素，出现存储不够用的情况时，此时就需要扩展逻辑分区或添加新的逻辑分区。下面介绍一下通过使用fdsik添加新的逻辑分区。
首先使用df命令检查文件系统的磁盘空间占用情况
[root@DB-ONE-SERVER~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-sda3
30G 2.4G 26G 9% /
/dev/sda1 99M 23M 71M 25% /boot
tmpfs 4.0G 0 4.0G 0% /dev/shm
You have new mail in /var/spool/mail/root
然后使用fdisk -l查看分区表信息
[root@DB-ONE-SERVER~]# fdisk -l
Disk /dev/sda: 42.9 GB, 42949672960 bytes
255 heads, 63 sectors/track, 5221 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 5221 41833260 8e Linux LVM
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdb doesn't contain a valid partition table
Disk /dev/dm-0: 32.3 GB, 32346472448 bytes
255 heads, 63 sectors/track, 3932 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/dm-0 doesn't contain a valid partition table
Disk /dev/dm-1: 10.4 GB, 10468982784 bytes
255 heads, 63 sectors/track, 1272 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/dm-1 doesn't contain a valid partition table
fdisk命令参数介绍
p、打印分区表。
n、新建一个新分区。
d、删除一个分区。
m、输出菜单
q、退出不保存。
w、把分区写进分区表，保存并退出。
[root@DB-ONE-SERVER~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won't be recoverable.
The number of cylinders for this disk is set to 2610.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
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): p
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-2610, default 1): 1
Last cylinder or +size or +sizeM or +sizeK (1-2610, default 2610):
Using default value 2610
Command (m for help): p
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 1 2610 20964793+ 83 Linux
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@DB-ONE-SERVER~]# fdisk -l /dev/sdb
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 1 2610 20964793+ 83 Linux
使用 mkfs.ext4 命令格式化磁盘成格式化成ext4各式的文件系统。
[root@DB-ONE-SERVER~]# mkfs.ext4 /dev/sdb1
mke4fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1310720 inodes, 5241198 blocks
262059 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
160 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 36 mounts or
180 days, whichever comes first. Use tune4fs -c or -i to override.
系统启动时自动挂载/dev/sdb1,编辑/etc/fstab文件，指定挂载目录为/u02
[root@DB-ONE-SERVER~]# vi /etc/fstab
/dev/VolGroup00/sda3 / ext3 defaults 1 1
/dev/sdb1 /u02 ext4 defaults 1 2
LABEL=/boot /boot ext3 defaults 1 2
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
/dev/VolGroup00/sda4 swap swap defaults 0 0
~
[root@DB-ONE-SERVER~]# cd /
[root@DB-ONE-SERVER/]# mkdir u02
[root@DB-ONE-SERVER/]# mount -a
[root@DB-ONE-SERVER/]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-sda3
30G 2.4G 26G 9% /
/dev/sda1 99M 23M 71M 25% /boot
tmpfs 4.0G 0 4.0G 0% /dev/shm
/dev/sdb1 20G 172M 19G 1% /u02
[root@DB-ONE-SERVER/]#
下面来看看虚拟上Linux的添加新的逻辑分区的步骤,其实操作是一样的，只是顺带介绍一下虚拟机如何添加硬盘
[root@oracle_server ~]# fdisk -l
Disk /dev/sda: 584.6 GB, 584646328320 bytes
255 heads, 63 sectors/track, 71079 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 19441 156151808 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 19441 44937 204796672 83 Linux
Partition 2 does not end on cylinder boundary.
/dev/sda3 44937 57685 102398336 83 Linux
Partition 3 does not end on cylinder boundary.
/dev/sda4 57685 71080 107595584 5 Extended
Partition 4 does not end on cylinder boundary.
/dev/sda5 57685 70433 102398336 83 Linux
/dev/sda6 70433 70949 4144768 82 Linux swap
/dev/sda7 70949 71080 1052288 83 Linux
Disk /dev/sdb: 146.1 GB, 146156158976 bytes
2 heads, 24 sectors/track, 5947109 cylinders
Units = cylinders of 48 * 512 = 24576 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 3 5947064 142729472 83 Linux
[root@oracle_server ~]#
此时需要选择“添加”选项，增加一个磁盘。
如下所示，我们选择“创建新的虚拟磁盘”
容量选择100G， 磁盘置备我们选择“Thin Provison”，表示用多少分配多少，最大分配100G，而不是一开始就分配100G（厚置被延迟置零）
[root@oracle_server ~]# fdisk -l
Disk /dev/sda: 584.6 GB, 584646328320 bytes
255 heads, 63 sectors/track, 71079 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 19441 156151808 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 19441 44937 204796672 83 Linux
Partition 2 does not end on cylinder boundary.
/dev/sda3 44937 57685 102398336 83 Linux
Partition 3 does not end on cylinder boundary.
/dev/sda4 57685 71080 107595584 5 Extended
Partition 4 does not end on cylinder boundary.
/dev/sda5 57685 70433 102398336 83 Linux
/dev/sda6 70433 70949 4144768 82 Linux swap
/dev/sda7 70949 71080 1052288 83 Linux
Disk /dev/sdb: 146.1 GB, 146156158976 bytes
2 heads, 24 sectors/track, 5947109 cylinders
Units = cylinders of 48 * 512 = 24576 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 3 5947064 142729472 83 Linux
此时使用fdisk -l 依然看不到添加的磁盘，此时可以通过重启或执行下面命令
[root@oracle_server ~]# echo "- - -" > /sys/class/scsi_host/host0/scan
[root@oracle_server ~]# fdisk -l
Disk /dev/sda: 584.6 GB, 584646328320 bytes
255 heads, 63 sectors/track, 71079 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 19441 156151808 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 19441 44937 204796672 83 Linux
Partition 2 does not end on cylinder boundary.
/dev/sda3 44937 57685 102398336 83 Linux
Partition 3 does not end on cylinder boundary.
/dev/sda4 57685 71080 107595584 5 Extended
Partition 4 does not end on cylinder boundary.
/dev/sda5 57685 70433 102398336 83 Linux
/dev/sda6 70433 70949 4144768 82 Linux swap
/dev/sda7 70949 71080 1052288 83 Linux
Disk /dev/sdb: 146.1 GB, 146156158976 bytes
2 heads, 24 sectors/track, 5947109 cylinders
Units = cylinders of 48 * 512 = 24576 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 3 5947064 142729472 83 Linux
Disk /dev/sdc: 107.3 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdc doesn't contain a valid partition table
[root@oracle_server ~]# fdisk /dev/sdc
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won't be recoverable.
The number of cylinders for this disk is set to 13054.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
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): p
Disk /dev/sdc: 107.3 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-13054, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-13054, default 13054):
Using default value 13054
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@oracle_server u04]# mkfs.ext3 /dev/sdc1
mke2fs 1.35 (28-Feb-2004)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
13107200 inodes, 26214055 blocks
1310702 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=29360128
800 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 32 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@oracle_server ~]$ more /etc/fstab
# This file is edited by fstab-sync - see 'man fstab-sync' for details
LABEL=/1 / ext3 defaults 1 1
none /dev/pts devpts gid=5,mode=620 0 0
none /dev/shm tmpfs defaults 0 0
none /proc proc defaults 0 0
none /sys sysfs defaults 0 0
LABEL=/tmp /tmp ext3 defaults 1 2
LABEL=/u01 /u01 ext3 defaults 1 2
LABEL=/u02 /u02 ext3 defaults 1 2
LABEL=/u03 /u03 ext3 defaults 1 2
LABEL=SWAP-sda6 swap swap defaults 0 0
/dev/sdb1 /u03/flash_recovery_area ext3 defaults 1 2
/dev/hda /media/cdrecorder auto pamconsole,exec,noauto,managed 0 0
/dev/fd0 /media/floppy auto pamconsole,exec,noauto,managed 0 0
vi
[oracle@get-orasvr02 ~]$ vi /etc/fstab
# This file is edited by fstab-sync - see 'man fstab-sync' for details
LABEL=/1 / ext3 defaults 1 1
none /dev/pts devpts gid=5,mode=620 0 0
none /dev/shm tmpfs defaults 0 0
none /proc proc defaults 0 0
none /sys sysfs defaults 0 0
LABEL=/tmp /tmp ext3 defaults 1 2
LABEL=/u01 /u01 ext3 defaults 1 2
LABEL=/u02 /u02 ext3 defaults 1 2
LABEL=/u03 /u03 ext3 defaults 1 2
LABEL=SWAP-sda6 swap swap defaults 0 0
/dev/sdb1 /u03/flash_recovery_area ext3 defaults 1 2
/dev/sdc1 /u04 ext3 defaults 1 2
/dev/hda /media/cdrecorder auto pamconsole,exec,noauto,managed 0 0
/dev/fd0 /media/floppy auto pamconsole,exec,noauto,managed 0 0
[root@oracle_server ~]# mkdir /u04
[root@oracle_server ~]# mount -a
[root@oracle_server ~]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 147G 86G 54G 62% /
/dev/sda7 1012M 34M 927M 4% /tmp
/dev/sda5 97G 73G 19G 80% /u01
/dev/sda3 97G 84G 7.6G 92% /u02
/dev/sda2 193G 133G 51G 73% /u03
/dev/sdb1 134G 74G 54G 59% /u03/flash_recovery_area
/dev/sdc1 99G 93M 94G 1% /u04