安装操作系统的时候，有一部分空间没有使用，在系统安装后，准备重新分区并格式化，在挂到/u01下，来安装Oracle的。

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 BootStartEndBlocksIdSystem

/dev/sda1*11310439183Linux

/dev/sda2146505116702+83Linux

/dev/sda36518411534207+82Linux 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

eextended

pprimary partition (1-4)

p

Selected partition4

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 BootStartEndBlocksIdSystem

/dev/sda1*11310439183Linux

/dev/sda2146505116702+83Linux

/dev/sda36518411534207+82Linux swap / Solaris

/dev/sda4842261014209492+83Linux

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.

关于Linux挂盘，参考Blog：

Linux下挂载硬盘的方法