Monday, June 29, 2009

‘File system with errors, check forced’ Linux Error and Recovery

Linux supports large no. of file systems like Ext2, Ext3 and ReiserFS. The latter two file systems support file system journaling, hence are less prone to file system corruption (as compared to Ext2) due to unexpected shutdown. Apart unexpected system shutdown, other causes that could corrupt these file systems are improper use of terminal commands, insufficient disk resources, user errors etc. While such situations, you cannot access your stored data and to restore it, you should use your recent data backup. But if backup fails or you find it non-existent, scan your hard drive using third party Linux recovery applications.

As a practical example, when you start your Linux-based system, you might receive the following error message:

contains a file system with errors, check forced”

You get another error message describing that you should run fsck manually.

You get such file system error message if one or more critical data structures are corrupted or damaged. Linux file systems are made up of data structures like, superblock, inode, extents, cylinder groups, and block bitmap etc, If any of these data structures get corrupt, you get errors like above.

You should try these fallowing steps to recover from such situations:

• First boot your system using Linux CD
• Enter the root password to enter into the terminal, when prompted for. It is recommended to enter in single user mode
• Run fsck on the affected partition with syntax: fsck
• Reboot the system
• If you still receive the same error message and file system is corrupt, you should recreate the file system by reformatting the hard disk. Formatting deletes all data, thus use your last backup to restore.

After formatting the hard disk, if you observe that backup data is damaged, not available and not updated; you need to use commercial
data recovery Linux tools. These are specific applications that use powerful scanning algorithms to examine the logically crashed drives. With read only design and self-descriptive interface, these Linux Recovery software allow you to perform safe and interactive recovery. You can use them in any logical data loss case.

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