101 4.1 create partitions and filesystems

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Junior Level Linux Certification

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Page 1: 101 4.1 create partitions and filesystems

Junior Level Linux Certification

Page 2: 101 4.1 create partitions and filesystems

Exam Objectives

Key Knowledge Areas

ext2 ext3 xfs reiserfs v3 vfat

Objective 4: Devices, Linux Filesystems, Filesystem Hierarchy Standard

Create partitions and filesystems Weight: 2

Terms and Utilities

fdisk mkfs mkswap

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File Systems

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FILE SYSTEM is the methods and data structures that an operating system uses to keep track of files on disk or partitionor, the way the files are organized on disk

Linux Filesystems can be created with the mkfs command.

Cmd is a front end to several filesystem-specific commands (such as mkfs.ext3 for ext3 and mkfs.reiserfs for ReiserFS)

To view what filesystem-specific support is installed on the system use: ls /sbin/mk* command.

Linux Swapspaces are created with the mkswap command.

Ex: yourname@yourcomp~> ls /sbin/mk*

/sbin/mkdosfs /sbin/mkfs.ext2 /sbin/mkfs.ntfs/sbin/mke2fs /sbin/mkfs.ext3 /sbin/mkfs.vfat/sbin/mkfs /sbin/mkfs.ext4 /sbin/mkfs.xfs/sbin/mkfs.btrfs /sbin/mkfs.ext4dev /sbin/mkhomedir_helper/sbin/mkfs.cramfs /sbin/mkfs.msdos /sbin/mkswap

Create partitions and filesystems

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File Systems

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Linux Swapspaces and Filesystems can be created with fdisk

Ex: yourname@yourcomp~> fdisk -v

fdisk (util-linux-ng 2.16)

yourname@yourcomp~> sudo fdisk /dev/sdb

[sudo] password for:The number of cylinders for this disk is set to 30401.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/sdb: 250.1 GB, 250059350016 bytes255 heads, 63 sectors/track, 30401 cylindersUnits = cylinders of 16065 * 512 = 8225280 bytesDisk identifier: 0x000404d6Device Boot Start End Blocks Id System/dev/sdb1 1 25 200781 83 Linux/dev/sdb2 26 12965 103940550 83 Linux/dev/sdb3 12966 30401 140054670 83 Linux

Command (m for help):

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Creating a swap space

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swap space from other partition with mkswap

Ex: yourname@yourcomp~> mkswap /dev/sda4

Setting up swapspace version 1, size = 4192960 KiBno label, UUID=8f5a3a05-73ef-4c78-bc56-0e9b1bcc7fdb

mkswap doesnt check if file or partition isn't used. It can overwrite important files and partitions

swap space is part of hard disk that is used as virtual memory

Linux can use a normal file in filesystem or separate partition for swap space.used as a raw partition, and will not contain any filesystem. type 82 (Linux swap);

Create partitions and filesystems

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Creating a swap space

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Ex: yourname@yourcomp~> dd if=/dev/zero of=/extra-swap bs=1024 count=1024 1024+0 records in 1024+0 records out

/extra-swap is the name of the swap file and the size of is given after the count=.

yourname@yourcomp~> mkswap /extra-swap 1024 Setting up swapspace, size = 1044480 bytes

After created a swap file or swap partition, you need to write a signature to its beginning; contains administrative information used by kernel. command to do is mkswap

Ex:

the swap space is still not in use: it will exist, but the kernel does not use it to provide virtual memory .

Create partitions and filesystems

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Creating a swap space

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initialized swap space is used with swapon. tells kernel that swap space can be used and path to swap space is given as argument

Ex:

yourname@yourcomp~> swapon /extra-swap

to start swapping on temporary swap file use the following command:

/dev/hda8 none swap sw 0 0 /swapfile none swap sw 0 0

startup scripts will run command swapon -a, which will start swapping on all the swap spaces listed in /etc/fstab

Ex:

Swap spaces can be used automatically by listing them in /etc/fstab file

swap space can be removed with swapoffswap used automatically with swapon -a can be removed from with swapoff -a; it looks at /etc/fstab to find what to remove

Create partitions and filesystems

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Creating a swap space

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monitor swap with free or top or in /proc/meminfo

View enabled swap devices use swapon –s or with cat /proc/swaps

yourname@yourcomp~> swapon –s

Filename Type Size Used Priority/dev/sdb1 partition 514044 0 -1/dev/sdb5 partition 4192928 0 -2

yourname@yourcomp~> cat /proc/swaps

Filename Type Size Used Priority/dev/sdb1 partition 514044 0 -1/dev/sdb5 partition 4192928 0 -2

Ex:

Create partitions and filesystems

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Creating an ext3 filesystem

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Ex: yourname@yourcomp~> mkfs -t ext3 /dev/sda8

mke2fs 1.41.9 (22-Aug-2009)Filesystem label=OS type: LinuxBlock size=4096 (log=2)Fragment size=4096 (log=2)2624496 inodes, 10488429 blocks524421 blocks (5.00%) reserved for the super userFirst data block=0Maximum filesystem blocks=4294967296321 block groups32768 blocks per group, 32768 fragments per group8176 inodes per groupSuperblock backups stored on blocks:32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,4096000, 7962624Writing inode tables: doneCreating journal (32768 blocks): doneWriting superblocks and filesystem accounting information: doneThis filesystem will be automatically checked every 20 mounts or180 days, whichever comes first. Use tune2fs -c or -i to override.

• To add journal to an existing ext2, use tune2fs with -j option.• To display or set label for ext2 or ext3, use e2label. Labels limited to 16 characters.

• To display UUID (Universally Unique Identifier) for the formatted partition, use blkid cmdLinux filesystems generate UUID when the filesystem is formatted - 128-bit identifier displayed as 32 hexadecimal digit and four

hyphens

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Other tools and filesystems

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cfdisk tool (console based)

Ex:

Create partitions and filesystems

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Other tools and filesystems

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gpart partitioning tool

Ex:

Create partitions and filesystems

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Linux file system

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Linux filesystem contains files arranged on a block storage device in directories.

Linux filesystem is a single tree with the / directory as its root directory.

Ex:

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File system Hierarchy Standard

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Directories required in / by the Filesystem Hierarchy StandardSet of requirements and guidelines for file and directory placement under UNIX-like operating systems.

Directory Description

bin Essential command binariesboot Static files of the boot loaderdev Device filesetc Host-specific system configurationlib Essential shared libraries and kernel modulesmedia Mount point for removable mediamnt Mount point for mounting a filesystem temporarilyopt Add-on application software packagessbin Essential system binariessrv Data for services provided by this systemtmp Temporary filesusr Secondary hierarchyvar Variable data

http://www.pathname.com/fhs/

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Filesystem Hierarchy Standard

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Ex:

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Linux file system

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A simple description of UNIX system, applicable to Linux, is:"On a UNIX system, everything is a file; if something is not a file, it is a process.”

• Regular files: Contain normal data. Ex. text files, executable files or progs, input for or output from a program.

• Directories: Files that are lists of other files.

• Special files: The mechanism used for input and output. Most special files are in /dev

• Links: System to make a file or directory visible in multiple parts of the system's file tree.

• Domain sockets: Special file type (similar to TCP/IP sockets) providing inter-process networking protected by the file system's access control.

• Named pipes: More or less like sockets. Form a way for processes to communicate with each other, without using network socket semantics.

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Linux file system

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The -l option to ls cmd displays the file type, using the first character of each input lineGood options are with -F and --color combined:

Ex: yourname@yourcomp~> ls -l total 80-rw-rw-r-- 1 jaime jaime 31744 Feb 21 17:56 intro Linux.doc -rw-rw-r-- 1 jaime jaime 41472 Feb 21 17:56 Linux.doc drwxrwxr-x 2 jaime jaime 4096 Feb 25 11:50 course

File types in ls -long list

Symbol Meaning•- Regular file •d Directory •l Link •c Special file •s Socket •p Named pipe •b Block device

File types in ls –Fsuffixes to non-standard file name. For mono-color use and printing

Character File type •nothing Regular file •/ Directory •* Executable file •@ Link •= Socket •| Named pipe

View info coreutils ls

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Fim de sessão

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