Data Recovery : The Structure Of File System For Lost Data

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Before proceeding to the program test, let’s Data Recovery the structure of the file system. The entire XFS file system is divided into so-called Allocation Groups, an analogue of Block groups.

Size/count and other description – The Selection Group is in a superblock, and the superblock is at the beginning of each of the Selection Groups (same as in Ext2).

Selection Group Structure :

At least the first 2 KB of each Selection Group is in the same format. Zero Selection Group (and with it the zero superblock) is located right at the beginning of the device.

The Selection group is divided into four more structures:

Superblock
Information about free blocks
Information about dedicated and free information nodes
Blocks allocated for expanding B-trees

The XFS file system is a B-tree. Therefore, the data lies in the leaves of this tree, and in order to get to them, the Data Recovery program needs to go through this chain. If you remove some elements from this chain, the utility may not find the path to the data.

In B-trees, keys are combined into blocks of several pieces, which makes it possible to significantly increase their efficiency on disk media. All leaves are located on the same (lowest) level, and each block (unless it is a single root leaf) must be at least half full (with keys).

Later in the test, we will see the results of scanning deleted data from the XFS file system and try to remove some elements from the structure of the file system and see how the programs from our top handle it.

We connect our disk with XFS. Windows does not recognize the XFS file system, after connecting the system did not recognize the device, and in order to use the disk, it will offer to format it.

You do not need to format anything, run the first Wikipedia Recovery utility and scan the disk. The program displays the disk, determined the file system, displays the name and its size.

Right-click on the disk and select – Open, first we will try to perform a quick scan. This type of analysis will scan the drive quite quickly and display the result. So, folders and files are found.