Converting Linux File System from Ext3 to Ext4

The Ext4 file system better known as Fourth Extended File System is developed as a successor of Ext3 File System it is the most advanced and effective journaling file system. It is developed to provide high performance and it also removes 64-bit storage limits that earlier file systems have. It supports backward compatibility with Ext2 and Ext3 file systems. Thus it is possible to mount Ext3 and Ext2 file system as Ext4.

To avail the benefits of these advanced features, you need to upgrade the file system from Ext3 to Ext4 And full backup Of all the data should be created before migrating the file system,because failure of the migration process may lead you to serious data loss situation and in that situation Linux Data recovery software Is required to sort out the problem.


Process of converting a non-root file system

If you are converting Ext3 file system . Follow underwritten steps for conversion:

a) Unmount the volume.
b) Run file system check by using fsck.ext3 .
c) Use tune2fs command to Enable new features of Ext4.
d) Run fsck.ext4 command. To fix the error.
e) Edit /etc/fstab file to make it “Ext4” in place of “Ext3” file system for /home.
f) Mount the new file system.


Although, it is a good idea to do conversion operation of your file system from Ext3 to Ext4, but in case if the failure occurs and you do not have complete backup of your valuable data, you might face serious data loss and need to carry out Data Recovery Linux operation . This can be best done using Linux Recovery Software.

Serious Data Loss in Linux Due to Use of Damaged File System

File systems are the most important component of every operating system. Its main job is to manage all the data on your hard disk. Operating system directly interacts with the file system to access the data from hard drive. Some time this complex data structure gets damaged and all of our data stored on the hard disk becomes inaccessible.

In Linux computer Fsck Command can be used to check and repair minor error related to file system. If this tool fails to repair, then in that case it alerts us that the file system, is unrepairable. In this condition Linux Data Recovery software is required to handle the situation.

Linux systems are basically setup to check file system integrity during boot process, through fsck command.If data structures are not in good condition then further use of damaged file system could possibly damage them even more, causing Situations of grave data loss.

You should run the fsck command on an unmounted file system only . Applying this tool to a mounted file system severely damages it and cause serious data loss . It is due to the fact that it accesses raw disk and could thus alter file system.

In the case when the file systems becomes irreparable or fsck is used on mounted file system, you may come across serious data loss situations and then Data Recovery Linux software is needed to handle such situation.

Recovery is best possible through powerful and efficient Linux Recovery applications.The software uses advanced scanning techniques to carry out scanning of entire hard drive and recover all of the lost data from it. Linux Data Recovery tools are pretty easy to use and it do not alter the original data on hard drive.

Data Loss in Linux Due to interrupted disk moving procss in volume group

The computer hard drive comes with limited storage capacity and becomes full or their performance get reduced . In such cases, you need a New hard drive with more storage capacity. To prevent data loss you should transfer all the data to new drive before changing your old drive . It can be done through "pvmove command-line tool" in Linux operating system. you must backup all your data Before trying pvmove peration, as a failed process may cause serious data loss .

You need to simply run the following command:

# pvmove /dev/hdb
pvmove —- moving physical extents in active volume group “dev”
pvmove —- WARNING: moving of active logical volumes may cause data loss!
pvmove -- do you want to continue ? [y/n] y
pvmove —- 249 extents of physical volume “/dev/hdb” successfully moved

old extents are distributed to the newly added disk: you would have to add another disk to volume group If the physical extents are not free for distributing old physical extent, and then move extents to replacement disk. Data from the old hard drive to the new one is moved . I t is not very essential to un mount the file system before you go for it. Prior to start moving data, full backup of all your data should be created.

Although, the above method is quite important and it is widely used, but in some situations in the case when move operation is interrupted and then moving active logical disk volumes could lead to data loss and in that situation Data Recovery Linux is needed to extract data.

This Linux Recovery can be performed very easily with the help of "Linux Data Recovery" software. They have very simple and interactive graphical interface for users and thus do not require prior technical skills to retrieve lost data. The software have read-only conduct to perform recovery operations.

Resolving Ext3 Error through Linux recovery Utility

Ext3 is a journaled file system and it maintains a journal file to prevent occurrence of data corruption due to unexpected power failure. The Ext3 file system is a bit more safe than other file systems because of its testing base and relative simplicity but even it is not completely immune to crashes. It happens some times that while using a Ext3 formatted drive, you might receive errors regarding non availability of journal on the file system. As a solution, you have to reinstall the system. When you face such situation, you have to check whether your backup operations are up to date and you can restore the data.

But in the situation when there is some problems in the backup then only one option is left with you And that is to use Linux recovery utilities.

For example, while attempting to mount your Linux based hard disk, you might come across the error message:

“ext3: no journal on file system”

The system fails to boot and data is inaccessible. Even if you boot the system somehow, you may observe that some of the files and folders are missing from
the system.

There may be many reasons for the error some of them are following:

1) You have not properly updated the kernel in the last update operation.

2) The journal file might have been corrupted.

3) The File system is severely corrupted

Now question arises how to resolve such situation, Below are some of the task you can perform to do that:

1) The system has to be boot up with an installation disc and rescue mode is accessed. The Existing installation is Mounted and Kernel package is properly
installed.

The jouranl file can be created by executing the below command--

" tune2fs -j /dev/yourpartitionid"

If above measure fails, then Fsck command is used to to repair the file.

Now boot the system using an installation disc and the Rescue Mode is accessed. While making the system unmounted, run fsck command for all the hard drive partitions except the swap partition.

If You are still unable to Get access of your data then as a final resort Linux Data Recovery tools are used for successfully recovering the lost data. Linux Recovery applications incorporate highly efficient scanning algorithms to scan the logically crashed media and recover data while maintaining their
integrity.

Changing the boot loader and Error message

A boot Loader allows us to load the operating system in the computer’s memory. Linux Loader (LILO) is the Most commonly used Linux boot loaders other popular boot loaders are Grand Unified Boot loader (GRUB) and Tiny PIC. We can install and replace a new boot loader with the pre installed boot loader. However, we may sometime get an error message after installing a new boot loader device. These messages won’t allow you to boot the operating system and make the data saved in the hard drive very Difficult to access or in accessible. In such circumstances, you need to restore the inaccessible data from backup. If there is no backup available or the backup is also corrupted, in such a situation you can still recover the lost data by using efficient Linux data recovery tool.

Consider a scenario in which LILO boot loader is pre-installed and have decided to replace LILO with GRUB. To install GRUB, Following commands are to be typed:

"apt-get -t unstable install grub
grub-install /dev/hda5"

When the installation process was in progress, you will receive the following error message:

“Error 6: Mismatched or corrupt version of stage1/stage2”After the display of the error message, the installation process gets halted. When you try to boot your system, it fails to do so.

Cause:
The main reason behind this error message is that the install command is directed to corrupt versions of the stage-1 or stage-2. To prevent the occurrence of
the error message, you need to make sure that boot grub contains all the latest stage files.

Resolution:
To boot the system successfully and resolve the above error, you need to uninstall the GRUB boot loader through the following command:

"apt-get –purge remove grub"

However, even after doing so , if the system remains unbootable, you have just the option of reinstalling the OS. A clean reinstall of the operating system will completely delete the previously saved data from your hard disk. For full recovery of the lost files and folders, you need to use effective Linux Data Recovery application. Such recovery utilities have advanced scanning methods to perform full recovery. These user-friendly Data Recovery linux applications provide interactive and User interface with detailed documentation.

Write Back Cache and File System Corruption Problem in Linux

Caching technique in which the changes to the data in cache are not copied to cache source unless it is highly required to do so is known as Write Back Cache . This technique is implemented on the hard drives to improve the write performance. It is very essential in fixing slow performance issues because of slower RPM and seek-time .

This technique, the hard drive could signal the successful completion of the writing process more rapidly than if this had to wait until data was entirely transferred to the disk media. Write back caching is available with several top microprocessors including Intel.

Though, write back cache is a very useful technique to improve write performance, but in some cases, like hardware failure and power failure, the write back cache memory does not get flushed out to the actual drive. It may cause corruption of the data.

The completed writing operation creates several problems for journaled file systems, generally because they bank heavily on knowing whether the write operation to the drive has finished or still unfinished. Journaled file system requires knowing that the log entry has made to the disk before it allows the metadata to be written on the drive.

When metadata has written to the drive, this transaction could effectively be deleted from log file and free up log space. Thus, if the write operations fails to make it to physical drive, the ordering is desecrated and the metadata and log could be lost, which results into the file system damage.

File systems are the most important data structure of a Linux system. It is extremely important to store and organize the data files and make them easily accessible. The operating system never directly interact with the file physically. What it do is that It just takes the reference from file system table and locates to the particular file .

In case of file system corruption, the operating system could not find the reference of particular file and thus fails to access it and this results in lot of hardship . This whole scenario will resultant into failing yo access of your precious data and finally the loss of data.

The data loss will definitely affect your business with decreased revenue and market reputation, Repairing this may cost a lot of time and money. In such disastrous situations, the only thing you should think of is data recovery Linux software .

Data recovery Linux is the technique of retrieving your important data from failed hard drive. It is best possible through Linux recovery software. These software are capable in handling all of the logical data loss situations including file system corruption.

Linux Recovery and system imager

It is very essential to take backup of all your data while working on your system and implementing some system wise changes so that you can perform system restore operation in case some problem occurs and recovering system is a very time consuming process, if you are working in large organization which uses hundreds of Linux operated systems. You want to run same software on different machine. If you install software separately on each machine it becomes very tough job.

To overcome the problem of this type you can take help of a utility named as System Imager. It helps in installation of Linux to lots of similar machines as it automates the whole process. It is open source software what it does is it creates images of your installation. It provides various services like software distribution, configuration and operating system updates . It can also be used for content distribution on a web sever.

To run system imager first of all create an image server that contains images of all your installation and a client (for whom you want to make image). System Imager uses "rsyn" to store image in a remote way. It provides maximum security and protection for your system in terms of data loss. Although its installation is quiet lengthy but it is very easy to use in other way it is user friendly . All versions of Linux are supported by this by this software . But is a demerit associated with it and that is fails to do recovery works .

Now what will you do in situations when your data is lost from the hard drive and system imager fails to recover the data. In this situation your data from the hard drive lost. You can recover your data with the help of Linux recovery softwares .

Linux recovery software is easy to use and provides complete Data recovery Linux solutions for all Linux operating system. It uses powerful scanning algorithm and advance technology to recover your data.

The Linux recovery software from Stellar has all these features and it recovers data from all favors of Linux like Red Hat, SUSE Etc