File System Corruption In Linux and Linux data recovery

Linux is a popular open source UNIX-like OS that organizes all your files in a tree structure. All the files are rooted at ‘/’ or root directory. In order to attach any file system of other drive to file tree, you are required to mount the drive. You can mount Linux drive using mount command. However, in some cases, the mount command fails to mount the drive and makes it ready for use. It makes your significant data inaccessible and causes serious data loss situations.

You might fail to mount a Linux hard disk is the file system of the disk is corrupt. File system corruption may take place due to numerous reasons, ranging from virus infection to hard drive crash. In a practical scenario of this problem, you may encounter the below error message when you try to mount a Linux hard drive

The Mount Command:
“mount: you must specify the filesystem type”
The error occurs every time when you run the mount command. It makes the drive unusable and put you in need of Linux recovery.

Root Cause
You may run across this problem due to any of the following reasons-
Improper editing of the fstab file. Linux uses this file to list out the available hard drives and volumes. The mount command uses this file to determine required

Options.
The disk volume does not contain any file system.
The hard drive file system is damaged.
Superblock is faulty and cannot be accessed by the operating system.

Solution
Use any of the below options to perform data recovery Linux in such cases-Use -t parameter with the mount command. Properly specify all the hard drive entries in the fstab file. It enables mount command to see all the available devices and options. Re-create the file system using mkfs.ext3 /dev/hdXX command.
Use fsck command to fix file system consistency issues.

Linux data recovery after boot block corruption

The Linux hard drive is partitioned in various partitions/volumes for effective management of your valuable data. Linux hard drive volumes start from the boot block where boot information of the operating system is stored. Last two byes of the Linux boot block contains boot block signature. In some cases, operating system cannot locate boot block signature and the disk cannot be accessed. It makes your significant data inaccessible and leads to data loss. Such cases require you to either restore data from backup or use Linux data recovery software to scan the drive and extract data from it.

For example, you might encounter an error message similar to the following one when you attempt to boot a Linux operating system based computer-

"Master boot record on /dev/hda has been updated.”
Subsequent to the above error, you may also encounter further error message that states-
“No boot signature found on partition”

The system cannot be booted in such cases and you face severe data loss situations. To recover your business-critical data in such cases, you are required to opt for Linux recovery tools.

Grounds of the issue

This problem most frequently occurs if you overwrite the LILO (Linux Loader) boot loader with the MBR (Master Boot Record) that was primarily installed on the /dev/hda disk volume. The boot loader might be overwritten if you try to install it using -M switch. Boot block corruption also results into the same problem.

How to fix boot block corruption problem?
In order to work around this problem, you have to overwrite the Master Boot Record with Linux Loader. It is possible with the help of /sbin/lilo Linux command. This command enables the operating system to overwrite MBR information on the /dev/hdX disk. Alternatively you can use LILO on the /dev/hda2 disk as:
boot=/dev/hda2
lilo -b /dev/hda2
lilo -M /dev/hda
lilo -A /dev/hda 2
In case the above method does not work, you will have to reinstall operating system. As reinstalling the operating system removes all the data from Linux partition, you will need data recovery Linux methods to get your precious data back.

Linux data recovery software employs highly-advanced Ext2 recovery algorithms to ensure absolute recovery. The advanced Ext3 recovery software are absolutely safe to use with read-only Linux recovery conduct.

How to recover linux file when boot error causes data loss

In case of a Linux operating system based computer, sometimes, the system fails to boot following any unsystematic system shut down. The reason can be anything from a possible file system corruption to an operating system malfunction, but at the end of everything, it is your valuable data in the drive, that has been inaccessible and you need to run any Linux data recovery software to recover them back.

Boot errors are always critical, as once you encounter those errors, your system fails to boot further resulting in the complete inaccessibility of your precious data in the drive. In a Linux system, there are many types of boot errors which may put you in trouble, one of them may be read as below:

“Creating Root Device

mounting root filesystem

(scsi:0:0:0:0) CRC error during data-in phase

(scsi:0:0:0:0) CRC error in intermediate CRC packet

scsi: aborting command due to timeout: pid 0, scsi 0, channel 0, id 0, lun 0 read (10) ......”

Once, you encounter the above error, the booting process of your Linux system halts infinitely and all your data becomes inaccessible till you resolve the issue.

Causes:

From the above error message, many users mistakenly think that there is certain hardware related problem, however, following are some of the reasons that are actually responsible for the problem:

Possible corruption or missing of /boot directory from the Linux installation files.

Possible file system corruption.

Linux data recovery utility when partition table is corrupted in linux

With technological advancement, now you can install and use more than one operating system in a single computer. This type of configuration, which is known as dual-boot, offers you to enjoy the features of multiple OS. However, sometimes, while making dual boot systems with different Linux OS the meta data structure gets corrupted. This kind of corruption results in the loss or inaccessibility of your valuable data and the need for advanced Linux data recovery arises to recover the data back.

In order to configure your system as dual-boot with another flavor of Linux, you are trying to install Fedora Core and come around a threatening error message. The error can be read as below:

“The partition table on device is corrupted. To create new partitions it must be initialized, causing the loss of all data on this drive”
After encountering the above error, the system may boot without any visible problem. However, if you go to the System Tools → Hardware browser, you will find out that the usual green bar for the hard drive is no longer there. The system is not showing the hard drive volumes and if you run the utility 'fdisk' on the drive, you may get a long set of messages. The messages that you receive, can be stated as follows:

“Disk /dev/hdc: 100.0 GB, 100030242816 bytes
16 heads, 63 sectors/track, 193821 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Device Boot    Start       End    Blocks   Id  System
Partition 1 does not end on cylinder boundary.
Partition 2 does not end on cylinder boundary.
Partition table entries are not in disk order”

Reasons for corruption

From the first error message as well as the the second one, it is almost sure that there is a possible corruption to the partition table of your system.

In Linux machines, partition table contains all the vital information about the hard drive partitions and these information are indeed extremely necessary for the operating system to access and manage the partitions. Therefore, if there occurs any problem to the partition table, data in the drive becomes completely inaccessible.

You can resolve the partition table corruption problems by formatting the hard disk and making a fresh installation of Linux. With formatting all your data from the drive will be erased and you need to restore them from a valid backup. However, if you do not have any valid backup, the only way to recover your valuable data back from the Linux hard drive is to run any efficient Linux Partition recovery software.

Data recovery Linux utility to recover your data in case of hard drive crash

Most of the Linux OS are open source applications and are regularly modified in order to safe-guard the system against any new threat in the form of viruses, malwares or  other technical drawbacks. An user can witness new changes and improvements in Linux  almost every day. In spite of all the good things, still there are occasions, which lead to the loss or inaccessibility of valuable data from your Linux system. Among such instances of data loss, hard drive crash is one.

Hard drive of your system contains many important data of yours' and anything like a crash of it can be an obvious hue and cry. However, with the help of advanced Linux data recovery, all your seemingly lost data can be recovered back.

When the hard drive crashes, though the data in the hard drive exists, you are unable to access the same. Apart from any physical damage, there can be many other problems behind the crashing of your hard drive, such as corruption of the file system, virus/malware infection, accidental deletion of the system files, operating system malfunction, other application contradictions etc. In any of these situations you may come across the following symptoms, which may signal a possible hard drive crash:

Symptoms of Linux hard drive crash:

The system is not booting properly or taking a much longer boot time.
Unusual black screen at the start-up.
After booting up, the Linux system hangs infinitely.
Some files, folders or even the drives are not listed surprisingly.
The system fails to recognize the hard drive/volumes.
The system stops responding in the middle of many operations or restarts quite often.
Flashes error messages indicating the damage to the file system or the corruption of Superblock etc.

In all the above situations, your precious data in the Linux hard drive is under serious case of data loss. However, you may be happy to know that under any instance of data loss, data from the media is never lost permanently, until that is being overwritten. Hence, if you take proper measures to avoid your data being overwritten and use any efficient Data recovery Linux utility, then, all your data can be definitely recovered back.

These Linux recovery software are developed with powerful algorithms to locate the lost or inaccessible data from the troubled Linux hard drive and recover them back with ease. Moreover, with highly interactive user interfaces, these utilities are easy to use even without much technical knowledge.

Linux data recovery solution when IV convert cause data loss

 'Ivconvert' is an in-built utility in Linux OS, which is meant to convert the linear logical hard disk volume to an exact or mirror logical volume. However, the point of caution is that if you do not handle the process carefully, it can lead to the failure of your hard disk and data loss thereof. Under such a condition, you need to take the help of any Linux data recovery software to bring back your lost or inaccessible data.

A brief about 'Ivconvert':

'Ivconvert' is an in-built application of Linux OS and helps you convert your liner Linux OS based hard drive volume to a mirror logical volume, which can be used in case, you encounter any instance of data loss situation. You can also use this command-line utility to add or remove the disk logs from the newly created mirror devices. Below are some of the most common parameters to perform some specific tasks:

• -R, --regionsize MirrorLogRegionSize- This option lets you divide the mirror disk into several regions of defined size in megabytes.

• -m, --mirrors Mirrors- This is a more advanced option, which lets you specify the degree of the mirror disk, you want to create. Note that here, '-m 1' means the original Linux volume to be converted into a single copy of mirror logical volume with one linear volume.

• --corelog- This is an option which instructs the utility to employ an in-memory log instead of a disk-based log.

• -s, --snapshot- This option allows you to create the snapshot from an existing volume with the help of another volume having the same origin.

• -Z, --zero y/n- This option defines the the zeroing of the first KB of information in the snapshot taken. However, if the volume is set as read-only, then the

snapshot can not be zeroed.

It is always safe to take the backup of all your important data before you try converting your Linux volume into a mirror one as if the process of conversion by 'Ivconvert' is stopped in the middle, it may lead to data loss/inaccessibility. However, if you have not taken any backup or you fail to restore data from the backup, you can use any Linux recovery software to bring back your seemingly lost data.

What to do when linux file system got corrupted

The Linux operating system is supposed to be the most regularly updated operating system among its counterparts. Apart from this fact, for its advanced technology and features, a large number of users prefer Linux. But, in Linux, the user can not get everything preloaded just like Windows. 

There is an unique command for each operation in Linux and from the long list of regularly used commands, the 'mount' command lets the operating system to learn about the file system and lists in the file system hierarchy of the computer, which lets us access the the particular drives. However, sometimes, the 'mount' command fails to work and the OS can not be able to learn the drives resulting in the inaccessibility of them. In such situations of data loss or inaccessibility, Linux data recovery can help you recover your valuable data back.

There can be a possible file system corruption, which has led this abrupt behavior of the Linux system following the failure of the 'mount' command. The 'fsck' is a built-in command-line utility in Linux operating system, which checks the consistency of the file system and repairs the same, if finds any error. After encountering the above situation, if you try to mount the drives using the 'fsck' command, you may encounter some more error messages. The error messages may be read as below:

"[/dev/mapper]fsck -a /dev/mapper/mpath0p1

fsck 1.35 (28-Feb-2004)

ext2fs_check_if_mount: Input/output error while determining whether /dev/mapper/mpath0p1 is mounted."

OR

"fsck.ext2: Bad magic number in super-block while trying to open /dev/mapper/mpath0p1

/dev/mapper/mpath0p1:

The superblock could not be read or does not describe a correct ext2

file system. If the device is valid and it really contains an ext2

file system (and not swap or ufs or something else), then the superblock

is corrupt, and you might try running e2fsck with an alternate superblock:

e2fsck -b 8193 "

The above error messages clearly state that the file system has been corrupted. In order to resolve the issue, you need to boot the Linux system from the safe mode and run the 'fsck' command to repair the corruption. However, if the file system has been severely corrupted, 'fsck' simply exits without doing anything. In such a case, if you are an expert user, you can input the next super-block address or the size of the same to the 'fsck' command, which can help the utility to gather the information from the next super-block and do the job.

However, failing to the above resolution method, you need to opt for any Linux drive recovery software to bring back your precious data.

Linux Hard drive Crashed what to do now

Are you annoyed by the crashing of your Linux machine regularly? The reason can be anything from virus infection, to accidental deletion of important system files and Linux hard drive crashes almost every time, you boot the system leaving all your valuable data inaccessible. However, you need not have to ponder on how to recover back your Lost critical data back, you just need to try any good Linux data recovery software .

You may encounter the below symptoms while encountering the crash of your Linux hard disk:

• Your Linux system fails to boot-up.
  
• You are receiving a blank or a dark screen when trying to boot your Linux system.
  
• The system is exceptionally slow and is taking a much longer boot time.
  
• You are frequently encountering the rebooting of your Linux system and hangs frequently.
  
• Getting an error message, such as: "No Fixed Disk Present" or "DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER".
  
• On start-up receiving error message, such as: "Operating system not found" or "Drive not formatted".
  

There can be a number of possible causes, for which you are encountering the above mentioned situations of data loss or inaccessibility from your Linux machine . To name a few, below are some serious and complex causes behind hard drive crash:

• Corrupted or damaged MBR.
  
• Deletion or missing of necessary system files.
  
• Corruption to the superblock of the hard disk.
  
• Corruption to the file system of the Linux hard disk.
  
• Deadly boot sector virus or malware infection.
  

In all the above data loss situations, first of all, you can try repairing your operating system by running the operating system CD. However, if you do not get any positive result out of it, try the 'fsck' command-line utility, which is meant to locate any file system based errors and fix them.

In case, you are still unable to resolve the issue, you have to format the hard-drive and make a fresh installation of the operating system. As formatting will erase all the data from the Linux hard drive, you have to restore them from a valid backup. If backup is unavailable, you have to use any Linux drive recovery utility to bring the lost/formatted data.