Essential needs of administration

Presented To:- Mr. Purushottam DasPRESENTED By:- Papu KumarSection:- BRoll No.:- 2061424(47)Semester:- III

TOPICS The Superuser: Root

Disks and Partitions

Making New Partitions

Mounting Filesystems

Mounting a Filesystem: mount

Mounting Other Filesystems

Unmounting a Filesystem: umount

Sample /etc/fstab

Filesystem Types

The Superuser: Root Every Linux system has a user called ‘root’

The root user is all-powerful

Can access any files

The root user account should only be used for system administration, such as installing software

When logged in as root, the shell prompt usually ends in #

Usually best to use su for working as root:

$ whoami fred $ su - Password: # whoami root

Concepts: Disks and Partitions

A hard disk provides a single large storage space

Usually split into partitions

Information about partitions is stored in the partition table

Linux defaults to using partition tables compatible with Microsoft Windows

For compatibility with Windows, at most four primary partitions can be made

But they can be extended partitions, which can themselves be split into smaller logical partitions

Extended partitions have their own partition table to store information about logical

partitions

Making New Partitions Create new partitions with the n command

Choose whether to make a primary, extended or logical partition

Choose which number to assign it

fdisk asks where to put the start and end of the partition

The default values make the partition as big as possible

The desired size can be specified in megabytes, e.g., +250M

Changes to the partition table are only written when the w command is given

Filesystems Some confusion surrounds the use of the term ‘filesystem’

Commonly used to refer to two distinct concepts

1. The hierarchy of directories and files which humans use to organise data on a system

(‘unified filesystem’)

2. The formatting system which the kernel uses to store blocks of data on physical media

such as disks (‘filesystem types’)

Disk Naming The device files for IDE hard drives are /dev/hda to /dev/hdd

hda and hdb are the drives on the first IDE channel, hdc and hdd the ones on the second channel

The first drive on each channel is the IDE ‘master’, and the second is the IDE ‘slave’

Primary partitions are numbered from 1–4

Logical partitions are numbered from 5

The devices /dev/hda, etc., refer to whole hard disks, not partitions

Add the partition number to refer to a specific partition

Changing Partition Types

Each partition has a type code, which is a number The fdisk command shows a list of known types

The command t changes the type of an existing Partition

Enter the type code at the prompt

Linux partitions are usually of type ‘Linux native’ (type 83)

Other operating systems might use other types of partition, many of which can be understood by Linux

Mounting Other Filesystems mount /dev/sdb3 /mnt/extra mounts the filesystem stored in

the /dev/sdb3 device on the

mount point /mnt/extra

You may occasionally need to specify the filesystem type explicitly:

# mount -t vfat /dev/hdd1 /mnt/windows

Allowable filesystem types are listed in the mount(8) manpage

To see a list of the filesystems currently mounted, run mount without any options

Configuring mount: /etc/fstab The /etc/fstab file contains information about filesystems

that are known to the system administrator

Specifying a filesystem in /etc/fstab makes it possible to use its mount point as the only argument to mount

/etc/fstab also configures which filesystems should be mounted at boot-up

Each line in /etc/fstab describes one filesystem

Six columns on each line

Sample /etc/fstab A sample /etc/fstab file: # device mount-point type options (dump) pass-

no /dev/hda3 / ext2 defaults 1 1 /dev/hda1 / boot ext2 defaults 1 2 /dev/hda5 / usr ext2 defaults 1 2 /dev/hdb1 / usr/local ext2 defaults 1 2 /dev/hdb2 / home ext2 defaults 1 2 none / proc proc defaults 0 0 /dev/scd0 / mnt/cdrom iso9660 noauto, users, 0 0 /dev/fd0 /mnt/floppy auto noauto, users 0 0

Filesystem Types The most common filesystem types are:

ext2 The standard Linux filesystem

iso9660 The filesystem used on CD-ROMs

proc Not a real filesystem, so uses none as the device. Used as a way

for the kernel to report system information to user processes vfat The filesystem used by Windows 95

auto Not a real filesystem type. Used as a way of asking the mount

Networked filesystems include nfs (Unix-specific) and smbfs (Windows or Samba)

Other, less common types exist; see mount(8)

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