Hack 65. Partition using fdisk

After you’ve installed brand new disks on your server, you have to use tools like fdisk to partition it accordingly.

Following are the 5 typical actions (commands) that you can execute inside fdisk.

  • n – New Partition creation
  • d – Delete an existing partition
  • p – Print Partition Table
  • w – Write the changes to the partition table. i.e save.
  • q – Quit the fdisk utility

Create a partition

In the following example, I created a /dev/sda1 primary partition.

# fdisk /dev/sda

Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous content won't be recoverable.

The number of cylinders for this disk is set to 34893.
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)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Command (m for help): p

Disk /dev/sda: 287.0 GB, 287005343744 bytes
255 heads, 63 sectors/track, 34893 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot  Start   End      Blocks   Id  System

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-34893, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-34893, default 34893):
Using default value 34893

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

Verify that the partition got created successfully

# fdisk /dev/sda

The number of cylinders for this disk is set to 34893.
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: 287.0 GB, 287005343744 bytes
255 heads, 63 sectors/track, 34893 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot  Start         End      Blocks   Id  System
/dev/sda1        1       34893   280277991   83  Linux

Command (m for help): q

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