HOW TO CREATE PARTITIONS in LINUX

 

We can  divide a single hard drive into many logical drives (like Partition 1, Partition 2 etc.) that is called partition.

It is logical blocks on a drive you can treated as an independent disk. A partition table is an index that relates sections of the hard drive to partitions.

                                                    

 

Disk Partitioning Criteria:

                                    MBR = MASTER BOOT RECORD
                                    P= PRIMARY PARTITION
                                    EXTENDED= EXTENDED PARTITION
                                    L= LOGICAL PARTITION
                                    FREE= FREE SPACE

We can divided disk into only 3 Primary Partitions.Primary Partition is a usually holds the operating system.
Extended Partition is a special type of primary partition We can be divided into multiple logical partitions. We have only 3 primary partitions per disk, and if the user is required to make further partitions there are the space remaining on the disk so user can be allocated to extended partition and user can used it  create the logical partitions later.

How Can Disk Identification

Different type of disks in Linux
                           IDE drive will be shown as /dev/hda
                           SCSI drive will be shown as /dev/sda
                           Virtual drive will be shown as /dev/vda

Types of file systems used in Linux:

The file systems supported in Linux O.S .We have ext2, ext3, xfs ,ext4, vfat in RHEL etc.
Ext file system is the widely used file system in Linux.

vfat is the file system to maintain a common storage windows .

Mounting Point in Linux:

(a) /etc/mtab:- is a file which stores the information of all the currently mounted file. it is dynamic and keeps changing.

(b)/etc/fstab is the file which is keeps information about the permanent mount point so that it will be mounted even after reboot .

   HOW TO CREATE FILE SYSTEM IN LINUX

Check partition using in linux :

                                                root@server~#fdisk –l or parted –l

Partition using fdisk

                                    root@server~#fdisk <disk name>
                                    root@server~#fdisk /dev/sda

                                                                 

 Use n to create a new partition using n and show list using p.

                                root@server~#fdisk /dev/sda   (ENTER)

                                  PRESS n

                                  first cylinder       select (Primary Partition)  

                                  second cylinder  pass size   +100G (Give Size)

                              command( m for help) p  (Show list)

Deleting a partition:-
                                       Use d to delete a partition

                                   

                                    command( m for help) d 

                                    partition no : 2  ( you want to delete choose)

Saving the partition changes:-

                                                  USE w to save changes

                                          
                                    command( m for help) : w

Lab Task :-

                 # fdisk -l
root@server~# fdisk /dev/sda
                               Command (m for help) : n
                               (type n for new partition)
                               (p - primary) or e - extended) : p
(type p for primary partition or type e for extended partition)
                        First cylinder : (press Enter for default first cylinder n                         Last cylinder : + <size in KB/MB/GB/TB>
Command (m for help) : t
                                                         (type t to change the partition id)
(for example: 8e for Linux LVM, 82 for Linux Swap and 83 for Linux normal partition)
                                Command (m for help) : w
(type w tosave the changes into the disk)
                            root@server~# partprobe /partx -a/dir1 /dev/sda1
(to update the partitioning information in partition table)

Mounting a partition

Mounting is a procedure where we attach a directory to the file system.

There are two types of

Temporary Mounting

A temporary mount point we will create a directory and mount it, but this mount point will last only till the system is up, once it is rebooted the mounting will be lost.

                           root@server#mount /dev/sda1 /dir1

Unmount Partition:
                           root@server#umount <mount point directory>
                           root@server#umount /dir1
                                                                    verify it with mount command.

Permanent Mounting

We can permanent mount the file system,but we have to update all details in this  file /etc/fstab , after mounted file system  we have to reboot the system.
Steps To make a permanent mount point:

root@server~

root@server~

root@server~

root@server~

How to see the size of the file or directory?

root@server~# du -h

(to see all the file sizes which are located in the present working directory)

To see the biggest files from current location)

root@server~# du .| sort -nr | head -n10

To see the biggest directories

root@server~# du -s * | sort -nr | head -n10

Assigning label to the partition:

Assigning the label is giving some name to the partition. To assign label to the partition e2label
command is used
Syntax
root@server#e2label <partition name> <label>
root@server#e2label /dev/sda7 ktdisk
To check the label
root@server#e2label /dev/sda7