主機自帶硬盤超過300GB，目前只劃分使用了3個主分區，不到70GB，如 下：
[root@db2 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 29G 3.7G 24G 14% /
/dev/sda2 29G 22G 5.2G 81% /oracle
tmpfs 2.0G 0 2.0G 0% /dev/shm
[root@db2 ~]# cat /proc/partitions
major minor #blocks name
8 0 311427072 sda
sda1
8 2 30716280 sda2
8 3 8193150 sda3
8 16 976896 sdb
8 32 976896 sdc
現在需要給系統添加1個100GB的空間存放數據文件，而又不影響現有系統上業務的運行，
使用fdisk結合partprobe命令不重啟系統添加 一塊新的磁盤分區。操作步驟如下：
第1步，添加新的磁盤分區
[root@db2 ~]# fdisk /dev/sda
The number of cylinders for this disk is set to 38770.
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)
Command (m for help): p
Disk /dev/sda: 318.9 GB, 318901321728 bytes
255 heads, 63 sectors/track, 38770 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 3824 30716248+ 83 Linux
/dev/sda2 3825 7648 30716280 83 Linux
/dev/sda3 7649 8668 8193150 82 Linux swap / Solaris
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Selected partition 4
First cylinder (8669-38770, default 8669):
Using default value 8669
Last cylinder or +size or +sizeM or +sizeK (8669-38770, default 38770): +100G
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.
Syncing disks.
[root@db2 ~]#
第2步，使用工具partprobe讓kernel讀取分區信息
[root@db2 ~]# partprobe
使用fdisk工具只是將分區信息寫到磁盤，如果需要mkfs磁盤分區則需要重啟系統，
而使用partprobe則可以使kernel重新讀取分區 信息，從而避免重啟系統。
第3步，格式化文件系統
[root@db2 ~]# mkfs.ext3 /dev/sda4
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
12222464 inodes, 24416791 blocks
1220839 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
746 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 (32768 blocks): done
Writing superblocks and filesystem accounting information:
done
This filesystem will be automatically checked every 26 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@db2 ~]#
第4步，mount新的分區/dev/sda4
[root@db2 ~]# e2label /dev/sda4 /data
[root@db2 ~]# mkdir /data
[root@db2 ~]# mount /dev/sda4 /data
[root@db2 ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 29753556 3810844 24406900 14% /
/dev/sda2 29753588 11304616 16913160 41% /oracle
tmpfs 2023936 0 2023936 0% /dev/shm
/dev/sda4 96132968 192312 91057300 1% /data
[root@db2 ~]#
總結：使用partprobe可以不用重啟系統即可配合fdisk工具創建新的分區。
