如果你在Linux系统中格式化磁盘时遇到如下错误，那么表示你正在格式化一个扩展分区。
[root@GETTestLNX06 ~]# mkfs.ext4 /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
mkfs.ext4: inode_size (128) * inodes_count (0) too big for a
filesystem with 0 blocks, specify higher inode_ratio (-i)
or lower inode count (-N).
直接格式化扩展分区是不允许的，只能格式化主分区和逻辑分区。那么那么应该如何格式化一个扩展分区呢，我们要么删除该扩展分区，创建一个主分区；要么在扩展分区上创建逻辑分区，如下操作所示
1： 创建逻辑分区
[root@GETTestLNX06 ~]# fdisk /dev/sdb
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): p
Disk /dev/sdb: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xd61351c9
Device Boot Start End Blocks Id System
/dev/sdb1 1 13054 104856223+ 5 Extended
Command (m for help): n
Command action
l logical (5 or over)
p primary partition (1-4)
l
First cylinder (1-13054, default 1): 1
Last cylinder, +cylinders or +size{K,M,G} (1-13054, default 13054):
Using default value 13054
Command (m for help): p
Disk /dev/sdb: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xd61351c9
Device Boot Start End Blocks Id System
/dev/sdb1 1 13054 104856223+ 5 Extended
/dev/sdb5 1 13054 104856192 83 Linux
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
2：格式化逻辑分区
[root@GETTestLNX06 ~]# mkfs.ext4 /dev/sdb5
mke2fs 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
6553600 inodes, 26214048 blocks
1310702 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
800 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, 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 28 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
3：将挂载信息写入配置文件
编辑[root@GETTestLNX06 ~]# vi /etc/fstab
4：挂载新建的分区
[root@GETTestLNX06 ~]# cd /
[root@GETTestLNX06 /]# mkdir u01
[root@GETTestLNX06 /]# mount -a
[root@GETTestLNX06 /]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_gettestlnx06-lv_root
44G 2.3G 40G 6% /
tmpfs 3.9G 0 3.9G 0% /dev/shm
/dev/sda1 477M 33M 419M 8% /boot
/dev/sdb5 99G 60M 94G 1% /u01
[root@GETTestLNX06 /]#
[参考资料]：