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Linux File System Series And Development – Ext2, Ext3 And Ext4

December 4th, 2012 Comments off

In Linux, ext stands for extended file system, first such type of file system, was implemented in April 1992 as  created specifically for the Linux kernel. This system is based on ‘metadata’ – very similar to traditional Unix File System (UFS). The development series of this file system was started from ext2 and today it has reached to ext4 as the latest file system available for Linux kernel.

To get the better idea of the development of this series, we will see features of all these three file systems developed for Linux Kernel.

ext2, ext3 and ext4 are all file systems created for Linux. This article explains the following:

Ext2

  • Ext2 stands for ‘Second Extended File System’.
  • This was introduced at the very start, in 1993. And, the developer was ‘Rémy Card’.
  • The main purpose behind its development was to overcome the limitation of the original ext file system.
  • One more thing about Ext2 is, it does not have journaling feature.
  • Ext2 is recommended mostly on flash drives and usb drives, as it doesn’t need to do the over-head of journaling.
  • For Ext2 Maximum individual file size limit can be from 16 GB to 2 TB
  • Overall ext2 file system size limit can be from 2 TB to 32 TB

Ext3

  • Ext3 stands for ‘Third Extended File System’.
  • This was introduced in 2001 and the developer was ‘Stephen Tweedie’.
  • Ext3 was available from  Linux Kernel 2.4.15
  • Allowing journaling was the most important feature of Ext3, which was absent in Ext2.
  • The major benefit of journalig is that it has a dedicated area in the file system, where all the changes are tracked, as a result the possibility of corruption of file system is minimized.
  • Maximum individual file size limit in EXt3 can be from 16 GB to 2 TB
  • Overall ext3 file system size limit can be from 2 TB to 32 TB
  • There are three types of journaling available in ext3 file system.
  1. Journal – This is the basic jornaling in which metadata and content are saved in the journal.
  2. Ordered – Only metadata is saved in the journal and metadata are journaled only after writing the content to disk. This comes as default.
  3. Writeback – Only metadata is saved in the journal but, unlike ‘Ordered Journaling’ Metadata might be journaled either before or after the content is written to the disk.
  • One can upgrade an ext2 file system to ext3 file system directly (without backup/restore).

Ext4

  • Ext4 stands for ‘Fourth Extended File System’.
  • Ext4 was introduced in 2008.
  • Ext4 was available from  Linux Kernel 2.6.19
  • One of the most important feature arrived in Linux file system with Ext4 was it has ability to support huge individual file size and overall file system size.
  • Ext4 made it possible to extend maximum individual file size limit from 16 GB to 16 TB
  • It also extended the Overall maximum file size limit to 1 EB (exabyte) (1 EB = 1024 PB (petabyte) and 1 PB = 1024 TB (terabyte)). So you can imagine how bigger overall file size can by supported by Ext4.
  • In Ext4 a directory can contain a maximum of 64,000 sub-directories (the limit is 32,000 in ext3)
  • Without upgrading one can also mount an existing ext3 fs as ext4 fs
  • Ext4 also introduced other important features like multiblock allocation, delayed allocation, journal checksum, fast fsck, etc. these new features play major role in improvisation in performance and reliability of the linux filesystem when compared to ext3.
  • Though journaling is an important feature, but in ext4, you also have the option of turning it off if not required.

Ext2 is becoming outdated package and today Ext4 is the most updated file system available for Linux, but still it is not used as widely as ext3 in web hosting services industry.

cPanel Cloud Hosting

March 6th, 2012 Comments off

cPanel is the leading Linux web hosting control panel, providing end-users with an intutivie and easy to use GUI that will allow them to manage their own web hosting accounts; WHM accompanies cPanel and allows resellers and system administrators to control their servers and accounts effectively. When combining cPanel hosting with a powerful cloud environment, you are able to offer a highly reliable and secure form of Linux cloud web hosting. As Linux is an open source operating system, cPanel cloud hosting services will be some of the cheapest cloud web hosting services available without compromising quality in any way and are likely to offer you a better level of service than some of the other cloud hosting solutions available. As a control panel cPanel is a web-based solution that is designed to allow web hosting customers to manage every aspect of their web hosting account without the need for any assistance, whilst remaining easy to use and easy for beginners to become accustomed to; whether you wish to add an additional email account your domain or change the permissions of a certain file, these tasks plus more complex ones can be easily achieved using cPanel. As a reseller hosting customer in the cloud then WHM will provide you with an interface from which you can manage your own hosting customers, add additional web hosting plans and create new customer accounts as and when they sign up; by choosing a cPanel cloud hosting plan you will be able to choose a reseller hosting plan that can provide you with a high level of uptime as well as generous resource allocations.

Benefits of cPanel Cloud Hosting

Many benefits can be had from choosing to use cPanel cloud hosting, some of which include, but are not limited to:

  • Low cost cloud hosting – by using cPanel and Linux in a cloud environment, web hosting services providers are able to offer low cost cloud web hosting that is affordable for all parties without compromising on the level of quality or uptime that is offered – for many businesses it is important to keep an eye on the outgoings and if it’s possible to save money in a certain area then it is important to embrace any opportunities that will allow you to do this – furthermore, there is no point in paying an extortionate price for a web hosting plan if you are sure that you can purchase a similar plan from another web hosting provider for a reduced sum of money
  • Intuitive web hosting control panel – cPanel is the most popular Linux web hosting control panel available and is used by a number of web hosting providers to offer Linux shared web hosting services – in the cloud cPanel will provide you with a reliable platform on which you can host your website and the services related to the control panel rarely fail, meaning that as long as the software if used in an environment that can offer unparalleled performance, such as a cloud environment, then you will be using a pretty much fail-proof hosting solution
  • Resource choices – the architecture of a cloud web hosting environment dictates that a number of servers are pooled together to provide the resource pool from which web hosting services can be formed – the power of having many servers clustered together in this formation allows web hosting providers to be very generous with the resources that they offer with their cPanel cloud hosting plans, therefore meaning that they will easily represent good value for money – depending on the hosting provider that you choose, there may also be the option to choose the resources for your cPanel cloud hosting plan based around your own specific needs.

Reseller Hosting with cPanel

cPanel is one of the best solutions available for resellers as you will have access to WHM (Web Host Manager), a control panel that is separate to cPanel and has been designed with system administrators and resellers in mind through the advance account and server management features that it provides. As a reseller hosting customer there are several features that you will want access to include:

  • Web hosting plan management
  • Client management
  • Feature management.

By providing the above, along with other features, in a separate control panel, cPanel has been able to develop the client-side control panel to be one that is better suited to beginners so that your clients are able to manage their own accounts easily.

Uptime Offered by Cloud Hosting

Any good web hosting company should be able to offer 100% guaranteed uptime with their cloud web hosting services, removing the worry of whether your website is going to be available or not. As multiple servers are clustered together to create a cloud hosting environment, if one server fails then there will be other servers available to pick up the slack of the crashed server until it is repaired and is ready for service again.

Compared to other forms of web hosting, a cloud hosting service is probably the most reliable hosting service available and this is without pushing the price up too much. For a long time the most reliable form of hosting has been dedicated server hosting and this has always been an expensive option; cloud web hosting has been able to provide those on a lower budget with the reliability benefits witnessed with cloud hosting, but at a much lower price that many will be able to justify and afford.

In conclusion, cPanel in a cloud environment is one of the best hosting combinations available, providing you with reliable hosting on a reliable platform at an affordable price. If you are a beginner then cPanel cloud hosting will be a good choice for you as the control panel interface is very intuitive and easy to use, with there being many tutorials available to provide you with assistance on completing a number of different tasks if you are unsure. Many providers will also offer full support with their cPanel cloud hosting plans giving you the ability to call on a professional support team if you are unsure of how to do something.

What Is LAMP?

January 28th, 2012 Comments off

We saw ‘What Is WAMP And WAMPServer’ in the last post, here we are going to learn about ‘LAMP’ which is nothing but a substitute to WAMP when one has hosted his website on ‘Linux Hosting Server’. LAMP consists of Linux, Apache, MySQL and PHP/Perl/Python, where Linux is an operating system, Apache is a Web Server, MySQL fulfills database requirements and PHP/Perl/Python work as scripting languages. The idea of LAMP was originally invented in 1999 by ‘Michael Kunze’ in a German magazine, though the four elements were not approached to work together but in the later period these open source applications were made available for free of cost and as a bunch called as ‘LAMP stack’. Because of having the ability to make a strong web application platform, LAMP gained the popularity in very early stage in such a way that in today’s market LAMP services are available as by default with almost all the website hosting services providers.

There are multiple security options available while using LAMP, you can configure Apache and PHP to remain hidden so that your information would not be leaked by any possible hacking attacks. You can find more about LAMP security at :- Is Your ‘LAMP’ Secure Enough?. LAMP tools are easily available with the features of easy configuration and being very robust. Being as an open-source application, LAMP is supported by the larger community, which constantly adds features and development to meet the requirements of it’s users. For deployment, configuration and maintenance of LAMP, one needs to spend very little effort and time, furthermore you don’t need any type of administrative details for it.

Is Your ‘LAMP’ Secure Enough?

October 21st, 2011 Comments off

As Security is one of the most important concerns in the internet world for webmasters, they should always keep their security system arrangements up to the mark, because hackers are always searching for new possible techniques to control your website and misuse it for their motive. Security measures can be classified in many categories, but a securing a website should cover security of web application as well as security of the web hosting server on which the web applications and website are hosted. Here I would like the share the information over security options on a LAMP (Linux, Apache, MySQL and PHP) as it is the most widely found combination among Linux Hosting Servers.
Instances in which a Web Hosting Server responds to the web browsers which are used by the visitors of the particular website residing on that particular website, that server provides a particular ‘header information’. Apache web servers are known for publishing many details of its environment as well as sometimes PHP also can be found responding in such header parts. Hackers may take advantage of this exposure in such headers of you website. Furthermore if he succeeds in knowing the factors like the type of web hosting services, type of server used, the web hosting platform, the version of scripting engine and other applications then it becomes an easy task for hackers to trace specific bugs or security loopholes. This makes the task easy for hackers to achieve their motives.
But still one can configure both Apache and PHP in such a way that it will remain hidden and will keep the possible attackers in the dark.

FTP Vs. Rsync?

September 27th, 2011 Comments off

Rsync is a great utility to manage downloads of transformation of Linux hosting servers and it is very easy to set up on a web hosting server. After technically studying it one comes to know that it copies only diffs of files which have been actually changed and compressed, through SSH. And this copying process is conducted without any scripted FTP session or any other format of file transfer script.

Following are a few concepts explained which are involved in ‘Rsync’ operations.
Diffs – Not the whole file, but only the changed portion of those files are transferred. This selective transformation makes the speed of update process faster. Unlike ‘Diffs’ FTP transfers the entire file though the change is very tiny.
Compression – The transferred small portions (Diffs) of the files are compressed while the transformation process is going on and this reduces the time required for transferring the Diffs. This also reduces the load on networks used for transformation.
SSH Encryption – With ‘Rsync’ security is provided on (a) higher level than the FTP because the stream from ‘Rsync’ is passed through the ssh protocol which encrypts your session and not the RSH.
Rsync can not be used with a windows web hosting server so one should approach other suitable utilities like ‘Robocopy’ or ‘Richcopy’.

Last Line Commands In VIM Editor

September 27th, 2011 Comments off

In previous posts we saw Cursor Movement commands, Text Modification commands, and commands used in Input Mode. In this post I would like to share the last line mode commands used in a VIM editor.
So following are the last line commands of VIM editor.
w – this command is used to save the file with the same name when you opened it to edit it.
w filename –  This command works as same as we use ‘save as’ with windows applications, which allows you to save the new copy of a file with your desired name. The substitute command to ‘w filename’ is ‘sav filename’, the same task of saving a copy of file with other name can be achieved by using ‘sav filename’ command.
n.m w filename –  this command is used for saving the content of line number ‘n’ to ‘m’ to the given file name. If you want to refer to the last line number (whatever it may be) then you should use ‘$’ instead of ‘m’.
e filename – This command is used to edit another file than the current one. It’s handy for toggling among the multiple files when used with the following ‘e#’ command.
e# – After using ‘e filename’ when you want to come back to previous file then you should use ‘e#’ command.
e! – This command is used to discard the changes made to a file.
r filename – This command reads the contents from a file and inserts it below the current line.

So these were last line VIM commands used to operate a Linux hosting server.

Text Modification And Input Mode VIM Commands

September 23rd, 2011 Comments off

Commands for Text Edition

In this post I have described the VIM commands used for text modification and commands used through Input Mode.
x – to delete the character which exists under the cursor.
rn – while using this command ‘n’ to be replaced with the character which you want to place in the place of any character under the cursor.
cw – this command puts you into input mode by replacing the current word at which cursor exists.
dw- to delete the current word on which cursor exists.
dd – to delete the current line in which cursor exists.
yy – to copy a line into the buffer.
P – to paste the copied line where the cursor exists.

Input Mode Commands

i – to insert text before the cursor.
I –  this works similar as ‘i’ but starts inserting text from the beginning of the current line.
a – to append text after the cursor.
A – this works similarly as ‘a’ but starts appending text at the end of the current line.
R – this command replaces characters which is currently under the cursor, it works similarly when we type the characters in windows with the insert key on. In short it is used for overwriting the current characters. To stop this command you should press the ‘Esc’ key.
o – to open the new line under the current line.
O – to open the new line above the current line.
Thus we saw the different VIM commands which are very handy while working on a Linux Hosting server or a Linux based system.

Cursor Movement VIM Commands In Linux

September 23rd, 2011 Comments off

In previous post we saw how important VIM commands are for handling a Linux hosting server, these commands basically come under Command mode of VIM
h – to move the cursor to left side
j – to move the cursor to down side
k – to move the cursor to up side
l – to move the cursor to right side
n| – to move the cursor to a particular character of the line, this is done by giving the that place’s number and if its valid the user notices a beep sound from the system. Entering just ‘|’ will move the cursor at the starting position of a particular line.
0 – to move the cursor at the beginning of the line
^ – to move the cursor at the first non blank character of a particular line.
$ – to move the cursor at the end point of a particular line.
fx – in this command you need to use any desired character in place of ‘x’ to move the cursor at the next appearance of that particular character used in the pace of ‘x’ within a single line.
Fx – it works similarly as ‘fx’ but in the reverse order, means you can fine previous appearance of the character placed instead of ‘x’.
[wW] – moves the cursor’s position word by word.
[bB] –  moves the cursor’s position word by word in reverse order.
H- to move the cursor at topmost line of your screen.
M –  to move the cursor at the middle line of your screen
L – to move the cursor at lowest line of your screen.
Ctrl-d – to scroll down the half page.
Ctrl-u – to scroll up the half page.
Ctrl-f – to scroll down the full page.
Ctrl-b – to scroll up the full page.
nG – in this command ‘n’ to be replaced by your desired number, which moves you to that particular numbered line of a file. i.e. if you typed 81G then you will be taken to the 81st line of that particular file.
Mx – in this command ‘x’ can be replaced by any single letter to which you want to comeback after going elsewhere. In short it is used for setting a line with a marker to be visited after the next move.
” – its command with two single quotes, and used for switching the positions simultaneously between two required places. In short it acts as a toggle.