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Red Hat Disk Management

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FDISK(8) Linux Programmer's Manual FDISK(8)

NAME
fdisk - Partition table manipulator for Linux

SYNOPSIS
fdisk [-u] [-b sectorsize] [-C cyls] [-H heads] [-S sects] device

fdisk -l [-u] [device ...]

fdisk -s partition ...

fdisk -v

DESCRIPTION
Hard disks can be divided into one or more logical disks called parti-
tions. This division is described in the partition table found in
sector 0 of the disk.

Linux needs at least one partition, namely for its root file system.
It can use swap files and/or swap partitions, but the latter are

You can use the fdisk or parted commands to create the appropriate partition sizes in the disk. To display the partition table, use the fdisk -l command. Refer to the man pages for the fdisk and parted commands for more information.

Disk partitoning task Solaris Linux
Create partitions on the disk format or fmthard fdisk or parted
Display partition table prtvtoc fdisk or parted
Maximum usable partitions 7 15 for SCSI, 63 for IDE
To create a file system on disk newfs or mkfs mkfs, mkfs.ext3, mk2fs -j, parted, or mkfs.reiserfs (SUSE only)
Check file system for consistency fsck fsck, fsck.ext3, e2fsck

Other considerations

In Solaris, you can create and use a maximum of seven slices per disk excluding the WholeDisk slice number 2.

In Linux, we have primary partitions and logical partitions contained in (primary) extended partitions.

Primary partitions and extended partitions can be created only in the Master Boot Record (MBR) of the disk and there is room for only four such partitions in MBR. Logical partitions are partitions created in extended partitions on the disk. The extended partition cannot be used directly, but only by means of the logical partitions created in it. To summarize, we can have up to four primary partitions, or one extended partition and up to three primary partitions defined in the MBR.

Using either the fdisk or parted command, you only need to create primary and logical partitions, and they then make the extended partitions automatically.

Another thing to note is that, in Linux, each partition has a partition type, which describes its intended usage. This type can be Linux, Linux LVM, Linux RAID, and so on. When creating a Linux partition, you decide what partition type to use. This depends on for what you intend to use the partition. If it is for data file system data storage, you will have to select ext2, ext3, Reiserfs, LVM, or one of the other options available. Refer to the man pages for the fdisk and parted commands for more information. The interactive fdisk command displays the available partitions types when you use the l subcommand.

# prtvtoc /dev/rdsk/c0t1d0s2
* /dev/rdsk/c0t1d0s2 partition map
*
* Dimensions:
*     512 bytes/sector
*     424 sectors/track
*      24 tracks/cylinder
*   10176 sectors/cylinder
*   14089 cylinders
*   14087 accessible cylinders
*
* Flags:
*   1: unmountable
*  10: read-only
*
*                          First     Sector    Last
* Partition  Tag  Flags    Sector     Count    Sector  Mount Directory
       0      2    00    1058304  20972736  22031039   /
       1      3    01          0   1058304   1058303
       2      5    01          0 143349312 143349311
       3      8    00   22031040 121308096 143339135   /space
       7      0    00  143339136     10176 143349311

 

# fdisk -l
Disk /dev/sda: 9100 MB, 9100369920 bytes
255 heads, 63 sectors/track, 1106 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

 

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1          64      514048+  82  Linux swap
/dev/sda2   *          65        1106     8369865   83  Linux

 


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Last modified: May 06, 2008