use of linux command fdisk to partition the raw device for ASM Disks

[root@oracle12cdb1 ~]# fdisk -l

Disk /dev/sda: 40.9 GiB, 43925766144 bytes, 85792512 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disklabel type: dos

Disk identifier: 0xb4face83

Device     Boot   Start      End  Sectors  Size Id Type

/dev/sda1  *       2048  2099199  2097152    1G 83 Linux

/dev/sda2       2099200 85790719 83691520 39.9G 8e Linux LVM

Disk /dev/sdb: 30.4 GiB, 32651509760 bytes, 63772480 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

[root@oracle12cdb1 ~]# fdisk /dev/sdb

Welcome to fdisk (util-linux 2.32.1).

Changes will remain in memory only, until you decide to write them.

Be careful before using the write command.

Device does not contain a recognized partition table.

Created a new DOS disklabel with disk identifier 0x01e28984.

Command (m for help): n

Partition type

   p   primary (0 primary, 0 extended, 4 free)

   e   extended (container for logical partitions)

Select (default p): o

Value out of range.

   p   primary (0 primary, 0 extended, 4 free)

   e   extended (container for logical partitions)

Select (default p): p

Partition number (1-4, default 1):

First sector (2048-63772479, default 2048):

Last sector, +sectors or +size{K,M,G,T,P} (2048-63772479, default 63772479): +10G

Created a new partition 1 of type 'Linux' and of size 10 GiB.

Command (m for help): n

Partition type

   p   primary (1 primary, 0 extended, 3 free)

   e   extended (container for logical partitions)

Select (default p): p

Partition number (2-4, default 2):

First sector (20973568-63772479, default 20973568):

Last sector, +sectors or +size{K,M,G,T,P} (20973568-63772479, default 63772479): +15G

Created a new partition 2 of type 'Linux' and of size 15 GiB.

Command (m for help): n

Partition type

   p   primary (2 primary, 0 extended, 2 free)

   e   extended (container for logical partitions)

Select (default p): p

Partition number (3,4, default 3):

First sector (52430848-63772479, default 52430848):

Last sector, +sectors or +size{K,M,G,T,P} (52430848-63772479, default 63772479):

Created a new partition 3 of type 'Linux' and of size 5.4 GiB.

Command (m for help): w

The partition table has been altered.

Calling ioctl() to re-read partition table.

Syncing disks.

[root@oracle12cdb1 ~]# fdisk -l

Disk /dev/sda: 40.9 GiB, 43925766144 bytes, 85792512 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disklabel type: dos

Disk identifier: 0xb4face83

Device     Boot   Start      End  Sectors  Size Id Type

/dev/sda1  *       2048  2099199  2097152    1G 83 Linux

/dev/sda2       2099200 85790719 83691520 39.9G 8e Linux LVM

Disk /dev/sdb: 30.4 GiB, 32651509760 bytes, 63772480 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disklabel type: dos

Disk identifier: 0x01e28984

Device     Boot    Start      End  Sectors  Size Id Type

/dev/sdb1           2048 20973567 20971520   10G 83 Linux

/dev/sdb2       20973568 52430847 31457280   15G 83 Linux

/dev/sdb3       52430848 63772479 11341632  5.4G 83 Linux