Corruption in Ext3 file system and its Recovery
Author: Garry ThomsonThe ext3 file system is a journaled file system which is commonly used by the Linux kernel. It is the default file system for many Linux distributions. The most important file in ext3 file system is journal., hence it is called a journaled file system. A drawback with ext3 file system is that it doesn’t support checksumming while writing to the journal and due to this; the file system gets closer to corruption and yje need of Linux Data Recovery is felt. Checksumming is generally defined as an error detection technique if the file is corrupted. But the problem is that the ext3 doesn’t support this feature, recovering from corrupt journal can damage all metadata information of file system.
The system crash is recoverable if the file system in-use supports journaling. But in ext3, if the mounting options in /etc/fstab don’t include barrier=1 as enabled plus hard drive is performing out-of-order write caching and system gets crashed, ext3 catches risk of corruption.
This barrier feature is disabled by default in all of the Linux distributions, except in openSUSE, and so these systems can lose data there is a crash. Also, if user tries to use the mount option for ex3, a warning is issued about barriers is not supported. In such cases also the system gets crashed.
In the above conditions the required blocks could be written, if user commits transaction and system crashes, it will reboot. During this, log replays and incomplete disk writing will be carried out with damaged journal information. This results into overwriting of normal data with that of damaged and hence file system corrupts. Data under these conditions can be recovered using Linux Recovery application. A good thing is that the successor of ext3 i.e. ext4 supports journal checksumming.
How to go for Linux Data Recovery
There are so many applications in market, available as Linux Recovery software, which can recover lost data from Linux systems with corrupt file systems. These applications can be used easily without any prior sound technical knowledge. These software are safe for recovering data as they are of read-only design.
The Stellar’s Linux Data Recovery Software is the one such powerful application to recover lost data from ext2, ext3 and reiserFS file systems. It has a graphically rich user interface. The software can recover data from most of the Linux distributions like Suse, SlackWare, Turbo Linux, Gentoo, Red Hat, Debian, Sorcerer and others. The application can work in almost all the types of data loss cases.
About the Author:Garry Thomson a student of Mass Communication doing research on linux data recovery software. He is also a freelancer for Stellar Information Systems ltd. .
Article Source: http://www.articlesbase.com/data-recovery-articles/corruption-in-ext3-file-system-and-its-recovery-870774.html