小知识：linux下使用fdisk结合partprobe命令不重启系统添加一块新的磁盘分区

主机自带硬盘超过300GB，目前只划分使用了3个主分区，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

现在需要给系统添加1个100GB的空间存放数据文件，而又不影响现有系统上业务的运行，

使用fdisk结合partprobe命令不重启系统添加 一块新的磁盘分区。操作步骤如下：

第1步，添加新的磁盘分区

[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让kernel读取分区信息

[root@db2 ~]# partprobe

使用fdisk工具只是将分区信息写到磁盘，如果需要mkfs磁盘分区则需要重启系统，

而使用partprobe则可以使kernel重新读取分区 信息，从而避免重启系统。

第3步，格式化文件系统

[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新的分区/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 ~]#

总结：使用partprobe可以不用重启系统即可配合fdisk工具创建新的分区。