分区的过程正常： [root@db1 /]# 
fdisk -l   Disk /dev/sda: 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/sda1   *           1          13      104391   83  Linux /dev/sda2              14         650     5116702+  83  Linux /dev/sda3             651         841     1534207+  82  Linux swap / Solaris
[root@db1 /]# fdisk /dev/sda   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)   Command (m for help): 
n Command action    e   extended    p   primary partition (1-4)
p Selected partition 4 First cylinder (842-2610, default 842): Using default value 842 Last cylinder or +size or +sizeM or +sizeK (842-2610, default 2610): Using default value 2610   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.  
再次查看，分区已经划好： [root@db1 /]# 
fdisk -l   Disk /dev/sda: 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/sda1   *           1          13      104391   83  Linux /dev/sda2              14         650     5116702+  83  Linux /dev/sda3             651         841     1534207+  82  Linux swap / Solaris /dev/sda4             842        2610    14209492+  83  Linux  
但是格式化的时候，报错： [root@db1 /]# 
mkfs -t ext3 /dev/sda4 mke2fs 1.39 (29-May-2006)
Could not stat /dev/sda4 — No such file or directory   The device apparently does not exist; did you specify it correctly?    
解决方法：执行下partprobe 命令          partprobe包含在parted的rpm软件包中。partprobe可以修改kernel中分区表，使kernel重新读取分区表。 
因此，使用该命令就可以创建分区并且在不重新启动机器的情况下系统能够识别这些分区。   查看是否安装该命令： [root@db1 dev]# 
rpm -q parted parted-1.8.1-23.el5   我们执行一下该命令： [root@db1 dev]# 
partprobe Warning: Unable to open /dev/hdc read-write (Read-only file system).  /dev/hdc has been opened read-only.  
然后在格式化，就ok了： [root@db1 dev]# 
mkfs -t ext3 /dev/sda4 mke2fs 1.39 (29-May-2006) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) 1778880 inodes, 3552373 blocks 177618 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=3640655872 109 block groups 32768 blocks per group, 32768 fragments per group 16320 inodes per group Superblock backups stored on blocks:         32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208   Writing inode tables: done                            Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done   This filesystem will be automatically checked every 38 mounts or 180 days, whichever comes first.  Use tune2fs -c or -i to override. 技术改变世界！ –狂诗绝剑