Using and Accessing Superblock Backup Copy in ext3

Ext2 and ext3 are the two most widely used file systems used for Linux. Superblock is the significant metadata structure that holds information like file system type, its status and size and information about other metadata structures. So if due to some errors file system becomes inaccessible, the reason could be superblock inaccessibility or corruption.

Superblock is required to access and hence mount the file system. In ext3 file system, it is about 1 kilobyte of information. Ext3 retains duplicate copies of superblock. So in case of superblock corruption or inaccessibility, we still can mount the file system that we may have considered a case of Linux Data Recovery.

While the actual position of first superblock backup is dependent upon file system size, recent large file systems generally find this superblock at block 32768. The mount options used for ext3 is –o sb. During superblock corruption, file system can be accessed, if we specify the location of superblock in 1024 bytes blocks with this mount option. We need to multiply the position of superblock (i.e. 32768) by 4 to get its second location (131072). For example the command will be -o sb=131072 /dev/hda5 /somewhere. After mounting the file system, we can use dd command to copy the backup superblock to the original location of superblock.

Note: These calculations are based on considerations that in modern file systems, block size of partition or volume is 4096 bytes. So we need to carry on accordingly.

But in cases when all the superblock copies become corrupt or user fails to mount file system using healthy superblock copy, Linux Recovery applications can be used to extract data. These are the applications that safely scan the media to offer Data Recovery Linux.

Linux Recovery software are interactive. Also they use powerful scanning algorithms to restore lost information. These Linux Data Recovery software can address major logical data loss issues with Linux.
Stellar Phoenix Linux Data Recovery is the renowned Data Recovery Linux product. It can scan the media using the most efficient scanning algorithms and safely restore the information. This Linux Recovery software offers safe data restoration options. Embedded with quality features, we can use it with ext2, ext3 and reiserFS file systems.