Hello everybody!
In this video, I’d like to show you a selection of best rated tools to recover lost data from
Linux volumes formatted into such file systems as Ext 4, 3 and 2.
Introduction By default, most modern Linux distributives
use the ext4 file system, in the same way as older distributives typically used ext3
or ext2 file systems, and the whole thing started one day in the past with them using
the original ext system.
One of the features within Ext2 is that the file system removes partially the information
about deleted files, in particular, links to file names, which makes recovering such
file names an almost impossible task.
On the contrary, Ext3 and Ext 4 are journaled file systems, and the process of removing
a file involves making certain changes to their journal.
The probability of recovering data from such systems depends largely on the size of the
journal and on how long the operating system worked after a certain file was deleted.
That is why it’s important to take immediate action right after you discover important
information was lost.
In our case, immediate action means you should stop writing data to the disk from where the
important information was removed, and find a reliable app to help you bring the files
back.
We have selected some of the most popular data recovery solutions which you may wish
to use, and conducted a few tests.
Watch this video to find out which of them can do better when it comes to recovering
lost information from the hard disk.
File system structure and the algorithm used to find the lost data
Before we start testing various tools, let’s explore the structure of these file systems.
This file system consists of a series of block groups.
The structure of each group begins with a Superblock followed by Group Descriptors,
then followed by Block Bitmap, then by Inode bitmap, then by Inode table, and the final
element is Data, that is, the information stored in a volume.
The Ext4 system is designed as a B-tree.
That is why the data is stored in its leaves, and in order to access the information, a
data recovery tool has to go down the chain of links before restoring any files.
If some elements of this chain are removed, there are chances that the data recovery tool
won’t be able to find the path to your data.
In today’s tests, we will try deleting some elements of the file system structure and
find out how best data recovery tools can cope with the problem.
Tests and benchmarks In Windows, you need a specialized utility
or a special driver to view the contents of a removable drive (such as a USB flash drive
or an external hard disk) formatted into EXT4/3/2.
Fortunately, data recovery tools can recognize such devices and restore data from them.
For our benchmarking assessment, we have selected several popular data recovery tools - Hetman
Partition Recovery, RStudio, EaseUS, Recuva and DiskDrill.
After a preliminary round of testing we had to exclude one of the participants - Recuva
- because it could find only a small portion of files on an Ext 4 drive.
Being able to recover only 20% of the lost data, it is evidently the tool least suitable
for the job, so we said goodbye to it.
All right, let’s get down to testing.
On a computer running a Linux operating system, we’ve created a test disk with Ext4 file
system.
Let’s copy some data there - for example, photos, videos, documents.
Remove some of the files and unmount the volume.
We will perform the tests on another computer running Windows 10.
Let’s connect the Ext4 drive.
Windows 10 can’t recognize this file system, and when the drive is connected, the operating
system suggests formatting it to be able to use it.
However, in fact there is no need to format anything - start Hetman Partition Recovery
and scan the drive.
You can see that the program can recognize the disk, detect its file system and display
its name and size properly.
Let’s try Fast scan first.
Here’s the result - the files and folders it can detect.
Evidently, this tool has no difficulty in finding the files deleted in such a way.
There is no need for Full analysis, and it saved us quite a lot of time.
Removed data is marked with a red cross.
All the files can be previewed and recovered without effort.
The disk structure is retained, so all files and folders can be located in a second: it
makes searching for specific data extremely easy.
The program has completed this test successfully and met the challenge just as we expected.
Let’s try another candidate, RStudio.
It can also recognize the test disk, detect its file system and display its name and size
properly.
Let’s try to view the drive contents.
Just as the previous program, RStudio finds all the files and preview is available for
all of them - except for documents.
The disk structure is retained; all other files can be previewed.
However, after a quick scan it can’t display contents of the documents.
That is why we will try a full scan now.
This time, the result is similar.
In the end, this tool has passed the test too, but it has some difficulties in displaying
documents.
Let’s move down the list to test EaseUS Data Recovery Wizard.
The program can display the drive, recognize its name and size.
However, the file system type is not displayed.
Let’s analyze the disk - and the program switches to Advanced Scan at once.
It can display all files now, but the disk structure is lost as well as file names, and
all the files are sorted by file type into separate folders.
The program seems to be checking the disk with in-depth analysis, so it’s going to
take a long time if you’re working with high-capacity drives.
Let’s check the results: the program has found all files and sorted them by file type
into folders.
It managed to find the documents, they can be previewed, all photos are available, and
one video file is damaged.
Unfortunately, deleted files have no markings to distinguish them from the files which are
still on the disk.
The only way to tell if all files are present is by counting them.
As you can guess, finding the file you need is going to be quite a challenge when there
are many of them on the disk, and it will take a long time to view every file.
The program has completed this test successfully, and only one video file couldn’t be recovered.
The next one on the list is DiskDrill.
It can recognize the drive, and display its name and size.
When we try scanning the disk, you can see there is no way to run a Quick Scan.
Only a Deep Scan can help us see what this product can do.
Here are the scan results: The program has found the data, but couldn’t
restore the disk structure or the file names, and sorted the files into folders by file
type.
All photos are available for preview and recovery, as well as the videos, one file is damaged;
all documents are present and can be previewed.
The program has coped with the task successfully, although it took quite a long time to complete
the scan; this may become a serious issue when you work with a high-capacity drive containing
a number of files - scanning the drive and looking for lost data may take much longer
than you expect.
All tools have passed the first test and showed good results.
In the next test, we’re going to erase main elements of the file system structure, one
after another: a superblock, then group descriptors table, then all superblocks - and see what
happens.
All right, for the second test, we’re erasing the superblock.
The search algorithm used in our product lets you recover data easily even when the file
system structure is damaged.
Hetman Partition Recovery allows us to analyze the disk space with the signature analysis
algorithm.
Analyzing the storage device sector by sector, the program finds certain byte sequences,
skips lost elements of the chain, and represents the data to the user.
If the entire file system structure is erased but level 0 folders are still there, data
recovery is still possible and our program will do its best to display and recover it.
Now let’s see how it works in real life.
Run Hetman Partition Recovery: it recognizes the disk and detects its file system type
and name.
Open the disk, choose fast scan.
We can see the same result as in the first test.
All the data is present and available for preview.
It goes without saying that all the files can be recovered.
The program has coped with the task successfully, even without running a full analysis.
The disk structure and file names are retained; all data is available for preview.
The second test is passed.
Now let’s try RStudio.
This program can also see the disk, display its name and file system type, so the result
is similar to the first test - you can’t preview documents, just as before.
Even after a deeper scan, nothing changed.
The disk structure and file names are retained, all data is present, so this program has also
passed the test.
The only downside is that it can’t show you the contents of the documents.
The next one on the list - EaseUS.
Just like in the previous test, the program can recognize the disk but doesn’t display
its file system type.
Let’s can it, then.
After scanning, nothing happens: just like before, files are sorted into folders, no
disk structure, no file names, but at least the files can be located, and documents are
displayed.
One video is damaged, and it’s unlikely we can recover it.
The program has passed the second test; meanwhile, we’re testing DiskDrill again.
The program can display the drive, recognize its name and size.
Quick scan is unavailable.
Let’s run a deep scan, then.
We can see the same result as in the first test.
No disk structure, file names are lost, but all data is present and can be previewed.
One file is damaged.
In the third test, we will erase the group descriptors table.
Let’s analyze the disk with Hetman Partition Recovery.
The program shows the same result as in the previous test.
You can see it on the screen.
Now let’s see what RStudio can do.
Nothing new - everything is just as before, the only change is that documents can’t
be previewed.
Still, the program managed to recover them in the end.
We can see the same picture when we run EaseUS, and you can see it now - one video file is
damaged.
All right, let’s see if DiskDrill can do better.
In the third test, DiskDrill has achieved the worst result.
The program failed to find the majority of the files - even those that haven’t been
removed.
However, the program suggests scanning the entire disk.
Okay, let’s see if it can improve the situation.
You know what?
Things are definitely getting better - all files are detected, including one damaged
video file.
All in all, this program has also passed the test, though it took more time than we expected.
Conclusion Now let’s draw the bottom line.
All the programs have passed the three tests, but with different results.
Hetman Partition Recovery managed to find all files, the disk structure and file names
are retained.
RStudio also detected all files, retained the disk structure and file names; although
documents can’t be previewed, we can still recover them.
EaseUS found all files too, but failed to keep the disk structure; all files are sorted
into folders by type, but their names are not displayed anymore.
One video couldn’t be recovered at all.
Finally, DiskDrill - it managed to locate all files, but it couldn’t display the disk
structure and file names - just like some other participants of this benchmark.
One video file is damaged.
The program managed to recover it, but only partially.
All right, now that you’ve seen the results, it’s easier to decide which tool to choose
for recovering your information, and which one is better suited for your needs.
The choice is yours, after all... but There is only one thing I’d like to add:
the algorithm used in our product allows to retain the folder structure and file names
which makes it easier to search for certain data and saves your time.
In addition, our program lets you create a disk image and then recover data from there,
which is the industry standard for dealing with faulty drives.
Some programs that we have tested today don’t have this feature.
The algorithm used in our product lets you recover data even if the entire structure
of the file system is erased, and if the disk has at least some data left, Hetman Partition
Recovery can restore it and display it to you thanks to using signature analysis.
That is all for now!
Hopefully, this video was useful.
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Thank you for watching.
Good luck.