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In Linux operating system, root file system is a file system, which is contained on the hard drive volume on which root directory is located. Linux kernel require the root file system to be mounted on startup. All other Linux file system are mounted on root file system. In some situations, this file system gets damaged due to virus infection and improper system shutdown like situations. At this point, your system can not boot up and all your valuable data become inaccessible and you come across data loss situations. In order to get your valuable data back, Linux Data Recovery is required.

In a practical scenario, when you attempt to boot your Linux computer, you may come across below error message:

“No root file system defined. Please correct this from the partitioning menu”

Although, the error message suggests you to correct this problem from partitioning menu, but you won’t find any option on screen.

Above error message terminates the boor process and system is rebooted. The same error message occurs every time when you try to boot the system. In such cases, to extract data from Linux hard drive, you are required to identify cause of this problem and perform Data Recovery Linux by sorting it out.

Root of the problem

As stated in above error message, this issue is generally caused by corruption to the file system of Linux hard drive partition on which operating system is installed. The same issue may also occur due to corrupted or lost hard drive volume.

Root file system corruption might take place due to a number of reasons that include:

Virus contaminations

Unexpected system shutdown

Power outages

Software or application malfunction

No matter what the cause of this issue is, it is essential to resolve it to get your valuable data back. For this purpose, Linux Recovery is there for your help.

Recovery can easily and quickly be performed using third-party applications, known as Linux Data Recovery software. The tools carry out in-depth scan of entire hard drive using powerful scanning algorithms and extract all of the lost, missing and inaccessible data from Linux hard drive.

The allow you to have straightforward recovery in all cases of data loss as they have interactive and simple graphical user interface. The software do not ever alter original data due to read-only design.

Stellar Phoenix Linux Data Recovery successfully retrieves lost data in such critical data loss situations. It supports recovery from Ext4, Ext3, Ext2, FAT32, FAT16 and FAT12 file system volumes. The software can be used by all major distributions of Linux operating system including Debian, Mandriva, SUSE, Fedora and Red Hat.

All the data files that are accessible in Linux based computers are placed in a big tree, called root directory and denoted as ‘/’, in an organized form. These data files might be spread out over various devices. The mount command in Linux operating system allows you to attach a file system on a data storage media to the root directory. However, if the file system is faulty and you run fsck utility to fix the problem after mounting the disk using this command, severe file system corruption occurs. It causes critical data loss situations and calls for Linux data recovery.

The mount command tells the Linux kernel to attach the file system found on your hard drive volume in the /dir directory. The previous owner, mode, and contents of the directory become invisible after mounting, and as long as the file system stays mounted, the /dir pathname refers to the root of file system on Linux hard drive volume.

The following three types of invocations of mount command don’t actually mount the volume:

·     mount -h- It prints the help message on screen.

·     mount -V- This invocation prints the version string.

·     Mount [-l] [-t type]- The option lists all the mounted file systems that are of type “type” on your Linux hard drive. The -l option adds labels (like ext2, ext3) in the listing.

In current versions of Linux operating system, it is possible to mark the mount and submounts as private, shared, unbindable, or slave. The shared mount gives you an option to create mirrors of the mount.

Mount is an essential process for accessing data from any Linux hard drive volume. If the drive is not mountable, it cannot be accessed. Sometimes, when you try to mount a Linux volume, you come across the following error message that puts you in need of data recovery Linux:

“Wrong fs type, bad option, bad superblock on /dev/hda8, missing codepage or helper program, or other error. In some cases useful info is found in syslog – try dmesg | tail or so”

This problem is caused by dirty or corrupt file system. In such cases, you need to use Linux recovery software to get your mission-critical data back. The Linux data recovery applications enable you to thoroughly scan the affected Linux hard drive using advanced scanning algorithms.

Stellar Phoenix Linux Data Recovery is the best solution to ensure absolute recovery in all Linux data loss situations. The software recovers lost Linux data from Ext4, Ext3, Ext2, FAT32, FAT16, and FAT12 file system volumes. It works well with all major distributions of Linux operating system, including SUSE, Mandriva, Red Hat, Debian, and Ubuntu.

Are you unable to change the ownership of your mountable Linux hard drive volumes to make them accessible on LAN? Does the process fail with both root user account and local account? Actually, this behavior occurs if you do not have appropriate permissions to change the ownership of the disk or some significant system files are damaged. Since the system files are damaged, they can not even be accessed by the regular users. This causes grave data loss situation and calls for Linux recovery, if the backup is not updated.

As a practical example of this problem, you may encounter the below error message every time you try to change the ownership of mounted hard drive on Debian Linux operating system based computer:

“debian:/# chown -v ryan:ryan /mnt/hdc1
failed to change ownership of `/mnt/hdc1′ to ryan:ryan
chown: changing ownership of `/mnt/hdc1′: Operation not permitted
debian:/# chmod -v 777 /mnt/hdc1
mode of `/mnt/hdc1′ changed to 0777 (rwxrwxrwx)
debian:/# ls -l /mnt/
total 16
drwxr-xr-x 4 root root 16384 1969-12-31 17:00 hdc1
debian:/#”

The “Operation not permitted” error may also occur if you try to mount a Linux hard drive volume, access data from a volume, move data from a location to another, or change the active partition.

Root of the problem:

This behavior may occur due to any of the below reasons and put you in need of Linux hard drive recovery alternatives:

One or more attribute bits of the directory or file are set incorrectly. It prevents you from changing disk permissions using the chmod command.

The root directory, which is repository of all sub-directories and stored data, is damaged. Thus operating system is unable to read structure of the disk.

System data structures, like file system, superblock, and iNode are either missing or corrupt. These reasons are responsible for making your Linux hard drive unusable.

Resolution:

To fix this problem, you need to repair or replace the corrupted data structures with new ones. It is possible by formatting the hard drive and reinstalling the operating system. But, this process eventually removes all your data from hard drive and causes further data loss.

In such cases, Linux hard drive recovery software come to your rescue. They are advanced commercial utilities, which thoroughly scan your hard drive using high-end scanning methods and retrieve all lost data. The Linux recovery tools are easy and safe to use.

Stellar Phoenix Linux Data Recovery software successfully recovers lost, missing, inaccessible, and deleted data from Linux hard drive. The software salvages data from Ext4, Ext3, Ext2, FAT32, FAT16, and FAT12 file system volumes of all major Linux distributions like SUSE, Debian, Red Hat, and Mandriva.

Like other computer operating systems, Linux also uses a number of data structures to perform various operations. These data structures include Superblock, root directory. Superblock is one of the most significant data structures, which contains all the basic information, such as file system type, status (either mounted or un-mounted), and size. In some situations, this data structure may get damaged and Linux cannot access data from hard drive. It causes critical data loss situations and requires Linux data recovery to be fixed.

Linux file system manager accesses the Superblock information for maintaining it. All the parameters, like size, defined in the Superblock must match the actual parameters; otherwise you may face critical problems. For example, if the size of is different in Superblock as compared to actual size, then disk is reported as corrupt and you run across critical data loss problem and need to opt for Linux recovery solutions.

As a practical instance of this issue, you might get the below error message when you try to access data from a Linux operating system based hard drive-

“The filesystem size (according to the superblock) is xxx

The physical size of the device is yyy.”

The above error most frequently occurs when you try to repair Linux files using the fsck command. The above error suggests that the file system size is mismatching and the partition is damaged.

Cause

You may come across this behavior in Linux operating system, if any of the below conditions are true-

An application or the system is attempting to write data on hard drive where Superblock is located. The problem occurs when Linux operating system prevents the application from writing.

The hard drive volume is damaged.
The file system, partition table, or the Superblock is damaged.
To perform data recovery Linux in such cases, you need to resolve this issue as soon as possible.

Resolution

Try out the below Linux data recovery methods to work around this behavior-
Boot your system in the single-user mode.
Run unmount -a command to unmount disk volumes.
Try repairing the Linux volumes using fsck command.
Resize Linux volumes with the help of resize2fs command.

In case the above Ext2 recovery solutions fail to work, opt for Linux data recovery software to extract your precious data. Such Linux recovery applications perform absolute data recovery Linux using advanced scanning techniques. They offer safe and easy Ext3 recovery.

Linux supports file systems like Ext2, Ext3, ReiserFS etc. They follow hierarchical directory structure, where everything starts from a root directory that is represented by ‘/’. The root directory then expands into sub-directories. As compared to Ext2 file system, Ext3 and ReiserFS are less prone to corruption. It is because they both support file system journaling and can replay journal to recover from unexpected crashes. But in cases of severe corruption, you need to use tools like fsck to repair the file system or ultimately format the partition or volume. To restore the lost data, you need to use an updated and valid data backup. But, if data backup itself gives errors or proves incomplete to deliver the required information, Linux Data Recovery tools can come to the rescue to recover your lost data.

Consider a scenario, you try to start a Linux system and receive a set of error messages as:

“Multiply claimed block”

The boot process fails with this error message and you can’t access the data.

Cause

When your system starts and it doesn’t find the file system in good state, it runs fsck check. This error message is returned by fsck check, when it finds the file system inconsistencies. File system can get corrupt because of unexpected shutdown, virus infection, network errors, hardware issues and other similar reasons.

Solution

To solve the ‘Multiply claimed block’ error, you need to follow these steps:

You need to manually run the fsck command. It can repair file system consistencies like the ones that occur when file system is unmounted or mounted as read-only.

If running fsck doesn’t resolve the issue, you need to reformat the hard disk and reinstall the operating system. This process recreates complete file system structure and also deletes all the data. In such cases, you need to use the recent data backup in order to restore the lost data. But in some cases, data backup can be corrupt or incomplete. To recover data during such circumstances, you can use commercial Data Recovery Linux applications.

Linux  Recovery software are advanced applications that use advanced scanning procedures to safely recover your lost or inaccessible data. Such software are available with interactive interface together with developed features to assist you.

Stellar Phoenix Linux Data Recovery offers powerful Data Recovery Linux solutions. It supports Ext2, Ext3 and ReiserFS file systems based Linux partitions and volumes. The software can be used with almost all Linux distributions as SlackWare, TurboLinux, SUSE, Mandrake etc. It gets installed on Windows (Windows Vista, XP, 2003 and 2000) and the affected Linux hard drive should be connected as slave.

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Linux people like to claim that directories are really just another type of file. This statement can be misleading. We saw in a previous article that you create a file using a file editor. We will see later in this article how to create a directory.

So just what is a Linux directory? A directory is a collection that may include one or more directories, one or more files, or in fact be empty. You may think of a directory as a computerized file folder or loose-leaf notebook that contains dividers (themselves directories) and pages (files.) Just like a notebook page may not contain a divider, a Linux file may not contain a directory.

Up to now our comments about Linux directories hold for Windows directories as well. Now let’s take a look at some differences between these two systems. First come the naming conventions. Linux always distinguishes between lower-case and upper-case characters in directory names. Microsoft Windows does not. For example, Linux treats pay12june and Pay12june are as two different directories, as different as the directories pay12june and heighho. These directory names were used as file names in the previous article. While Linux does have some reserved directory and file names, in general one cannot tell by the name whether it is a file name or a directory name. So be careful. Linux helps you out here ‘ the ls command that lists the contents of a given directory usually displays files and directories in different colors.

Directories are hierarchical. They resemble a tree or a family tree. But unlike a tree (or Microsoft Windows) Linux has only one root. The root, designated as / lies at the top, rather than at the bottom, of the hierarchy. Right underneath the root directory you will find several subdirectories. For example, the /home directory is a child of / the root directory. The number and names of the first-level subdirectories vary from one version of Linux to another. For example, some Linux distributions include a /root directory while others do not. The /root directory (or subdirectory, both terms are used) is a child of /, the actual root directory.

The /home directory is an important directory. It is divided into subdirectories, one for each user. We like to work with Damn Small Linux, a free version of Linux that runs on the Windows desktop and requires only 50 Megabytes of disk space. Damn Small Linux automatically creates a user called dsl whose home directory is /home/dsl ; a working area essentially reserved for this user. All Linux versions subdivide the /home directory into user subdirectories according to this simple naming convention.

Linux provides several commands to process directories. For example, the mkdir command creates a directory. The rmdir command removes a directory, but in the simplest case only when it is empty. The cd command changes the working directory, the directory in which you are positioned. The pwd (print working directory) command displays (not prints) the working directory. Beginners should run this command often to reduce errors. For example, if you, the dsl user, think that you are positioned in the /home/dsl directory but in fact are positioned in the / directory you won’t be able save your files with a simple command. Why? Because you lack the requisite permission, the subject of our next article.

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Are you finding difficulties in mounting your Linux system disk? The problem could be due to corruption in the file system. To address such issues, Linux OS provides fsck utility. It is a command-line utility, which checks integrity and consistency of the Linux file system. In addition, it finds errors and fixes them, if possible. However, if you run this utility on a mounted file system, then you may not be able to access the data at all. In such cases, you should use a third-party Linux data recovery software to perform data recovery Linux system.

Consider a scenario wherein you have accidentally run fsck on a mounted Linux OS. The inode root gets damaged and all inodes start calling similar blocks. When you try to mount the volume after fsck, the following error message is discovered:

“Mount: wrong fs type, bad option, bad superblock on /dev/hda1, missing codepage or helper program, or other error. In some cases useful info is found in syslog – try dmesg | tail or so”

When you run \dmesg\, as suggested in the error message, another error message may be displayed, that is:

“ext3-fs: corrupt root inode, run e2fsck”

And when you run e2fsck, yet another error message is displayed, that is:

“Root inode is not a directory. Clear?”

Once you press ‘Y’ and proceed with the process, the parent entry of each inode from the root directory will be deleted. The root inode will attempt to recover but if it fails, another error message will be displayed, that is:

“Cannot Allocate Root Inode”

After this error message, you will not be able to access your system.

Cause:

This behavior is caused due to corruption of the file system, superblock, root inode, or any other Linux data structure. Because of this, the OS cannot locate the hard disk volumes.

Resolution:

To sort out this problem and perform Linux data recovery, you should reformat the hard disk and reinstall the Linux operating system. However, that would invariably mean that your valuable data will be lost. In such cases, you should use a third-party Linux recovery to recover lost data. Such tools are able to recover lost data safely by using fast yet sophisticated scanning algorithms.

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