Data Recovery from ZFS RAIDZ1, RAIDZ2, RAIDZ3, and Stripe Arrays

⭐⭐⭐⭐⭐ In this video, we will examine the procedures for recovering data from RAIDZ1, RAIDZ2, RAIDZ3, and ZFS Stripe arrays created in the TrueNAS SCALE operating system. We will demonstrate the sequence of actions in the event of a serv er hardware failure and the methodology for restoring access to a data pool when one or more drives fail or when information is accidentally deleted from the array.

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👉 Synology DS418play NAS: data recovery from SHR-2 and SHR-1 RAID arrays - https://hetmanrecovery.com/recovery_news/how-to-recover-data-from-shr1-shr2-on-synology-ds418play

📚 Content:
00:00 - Intro
01:23 - TrueNAS SCALE Capabilities
02:41 - Automatic Recovery of ZFS Arrays
06:38 - RAIDZ Recovery Without Several Disks
09:53 - Recovery of Deleted Files
12:41 - Conclusion

RAID Systems: Definition, Types, How to Create One and Recover Lost Data - https://www.youtube.com/playlist?list=PLWfvrWYvsWiJznrhRlxOKYd40Z1sOP2Vf

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Other videos: #ZFS #RAIDZ #RAIDZ1 #RAIDZ2 #RAIDZ3 #DataRecovery #Storage #NAS #Server #Tech

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Closed Caption:

In this video, we will examine the
procedures for recovering data from
RAID-Z1, RAID-Z2, RAID-Z3, and ZFS
stripe arrays created in the TrueNAS
SCALE operating system.
We will demonstrate the sequence of
actions in the event of a server
hardware failure and the methodology for
restoring access to a data pool when one
or more drives fail or when information
is accidentally deleted from the array.
In addition to hardware malfunctions, we
will consider data recovery after
deleting an entire data set, pool
corruption, critical operating system
crashes, ZFS file system damage, errors
when adding new disks, incorrect
controller operation, and accidental
drive initialization in another system.
The data recovery process takes place in
the Linux Ubuntu operating system, but
it is also possible in Windows and macOS
environments.
The Hetman RAID Recovery program
automatically detects connected disks
and the array configuration, regardless
of the platform, and allows for the safe
recovery of files and folder structures
in any of these systems.
Using Hetman RAID Recovery, you can
successfully restore access to files
even in cases of critical array failures
or hardware damage to the server.
The program allows for the safe recovery
of data from damaged or deleted pools
and data sets while preserving the file
and folder structure.
TrueNAS is an open-source operating
system for building network-attached
storage, NAS, based on Linux and
utilizing the ZFS file system.
It provides data protection, integrity
checking, efficient disk management, and
supports running virtual machines.
The platform supports various RAID
types, including RAID-Z, which combines
performance and fault tolerance.
TrueNAS SCALE allows for horizontal
scaling by combining multiple nodes into
a cluster while maintaining key ZFS
functions: data self-healing, snapshots,
compression, deduplication, and
encryption.
The system is compatible with SMB, NFS,
iSCSI, and S3 protocols, and also allows
for running containers and Kubernetes,
making it a versatile solution for data
storage and processing in various
environments. RAID-Z is a redundant
array of disks in ZFS with distributed
parity. The use of variable length
blocks optimizes writing and allows for
automatic error correction during
reading.
When recovering a degraded array,
resilvering, the load on the other disks
increases significantly.
Therefore, RAID-Z is best suited for
environments with moderate fault
tolerance requirements, or for small
capacity disks where the array recovery
time is minimal.
In the event of a failure of hardware
components of the server, such as the
power supply, motherboard, or disk
controller, direct access to data from
the operating system becomes impossible.
Such situations also arise when the
server stops booting due to a critical
error during a TrueNAS SCALE update, or
if the system partition is corrupted.
Even if the files and disks are not
physically damaged, access to the RAID-Z
array may be lost, and standard ZFS
tools may not allow you to see the
drives or import the pool.
In these cases, specialized software,
such as Hetman RAID Recovery, allows you
to safely gain access to the data and
recover the information.
In this example, we will show the data
recovery process in automatic mode on a
computer running Ubuntu.
First, turn off the server and carefully
remove all the disks that were part of
the array.
Connect them to a workstation. The
optimal option is a direct connection to
the motherboard via SATA cables for
maximum speed and data transfer
stability.
If the motherboard lacks free ports, you
can use external USB docking stations or
USB adapters for the disks.
Keep in mind that when connecting via
docking stations, the scanning speed may
be lower. So, for large volumes of data,
it is preferable to use internal ports.
After connecting, check that the disks
are displayed in Ubuntu in the disks
application, but do not initialize them
if the system prompts you to do so.
Immediately after checking, proceed to
launch Hetman RAID Recovery to
automatically assemble the array.
A key feature of Hetman RAID Recovery is
its deep analysis of ZFS metadata. The
program does not need a functional
operating system or controller. It reads
service information directly from the
disks and automatically recreates the
pool structure.
Since ZFS stores all critical data about
the array configuration within the pool
itself, the logical integrity of the
files is preserved even in the event of
complete server environment
unavailability. As a result, the user
gains access to the data in a familiar
form without being dependent on the
original system.
In this video, various array
configurations are used for
demonstration. RAID-Z1 on three disks,
RAID-Z2 on four disks, RAID-Z3 on five
disks, and a stripe array on two drives.
We will examine the recovery algorithm
for a RAID-Z1 array of three disks,
specifically for a situation of complete
hardware server failure or a critical
error after a TrueNAS Scale update.
Importantly, this approach is universal
and can also be applied to RAID-Z2,
RAID-Z3, and stripe configurations.
After launching, Hetman RAID Recovery
automatically performs a scan of all
connected devices. The program reads the
ZFS service metadata, analyzes the
configuration of VDEV virtual groups,
and restores the correct RAID-Z1 model
based on the data obtained.
The main window displays the detected
drives and the assembled logical
structures. You can immediately continue
working with them, perform a detailed
analysis, view the data structure, or
recover the necessary files.
Select the required RAID-Z1 from the
list of reconstructed arrays and start
the fast scan mode to quickly determine
the data structure.
Once the scan is complete, the recovered
file system with its full hierarchy of
directories and files will be displayed
in the main window.
Select the necessary objects and click
recovery.
In the next step, specify the folder for
saving the data, preferably on a
separate storage medium with sufficient
free space. Confirm the start of the
process, specify the final save path,
and click recovery again to begin
copying.
After the operation is complete, click
finish. Ultimately, the data from the
ZFS RAID-Z1 pool will be recovered and
become available for further use in its
usual form.
Now, let's consider a case of failure of
one or more disks in a RAID-Z array.
RAID-Z architecture provides fault
tolerance depending on the type of
array.
RAID-Z1 allows for the loss of one disk.
RAID-Z2 allows for two. RAID-Z3 allows
for three.
In the case of a stripe array, there is
no redundancy, so the failure of any
drive leads to total data loss.
If it is not possible to connect all the
disks, you can create an image of the
missing drive and use it along with the
other disks for further recovery.
Thanks to distributed parity mechanisms
and data integrity control, specialized
software, specifically Hetman RAID
Recovery, is capable of reconstructing
lost blocks and restoring access to
information as long as the number of
failed disks does not exceed the allowed
level for the specific RAID-Z type.
If this threshold is exceeded, the
logical structure of the array is broken
and standard software methods become
ineffective.
In such situations, recovery is only
possible using professional equipment in
specialized laboratories.
Ensure that the target medium has
sufficient free space to save the
recovered data.
Carefully remove the disks from the
server and connect them to the computer
via SATA ports or an external docking
station.
It is important to avoid writing any new
data to these drives as this could lead
to irreversible data loss.
If the architecture of your workstation
does not allow for connecting all disks
simultaneously, the optimal solution is
to use virtual disk images.
This method involves creating exact
bit-by-bit copies of each disk for
further analysis.
Detailed instructions for creating
images are available in previous videos
on our channel.
Let's break down the data recovery
process using the example of a RAID Z3
array in which three disks failed
simultaneously.
This array configuration allows for data
recovery even in the event of such a
serious failure.
We will perform this using the Hetman
RAID Recovery Utility.
Immediately after opening, the program
independently checks all connected
drives, reads the service information,
and restores the original array
structure based on it.
Select the found RAID Z3 and activate
the fast scan mode.
As soon as the check is finished, the
full structure of the reconstructed
array with all directories and files
will be displayed in the working window.
Select the required elements and click
recovery.
Then, specify the folder for saving and
confirm the operation by clicking
recovery again.
When copying is complete, click finish.
After completing all stages, the
recovered files from the RAID Z3 array
will be fully usable in standard mode.
Finally, let's look at one of the most
common situations, accidental deletion
of files from a RAID array.
In this example, we are recovering data
from a stripe array created from two
disks under the ZFS file system.
The peculiarity of a stripe array is
that data is distributed across all
disks without any redundancy.
This means that no single disk contains
complete files.
For successful recovery, you need to
connect all disks simultaneously and
work with the array as a single logical
structure.
If one of the disks is missing or not
connected, the program will not be able
to read the data.
Before starting, make sure all disks are
physically connected to the computer,
either directly via SATA to the
motherboard or using an external docking
station.
It is critical not to write new data to
these disks and not to initialize them
in the system to avoid overriding the
lost files.
In Ubuntu, launch Hetman RAID Recovery.
The program will automatically perform a
scan of all connected disks, read the
ZFS metadata, and recreate the logical
structure of the stripe array based on
it.
In the main window, you will see the
physical disks and the already assembled
array ready for operation.
Next, select the stripe array in the
list of detected arrays and launch the
full scan mode.
A full scan is necessary because after
files are deleted in ZFS, only a deep
analysis allows the program to collect
data fragments and restore the correct
folder structure.
Additional settings are usually not
required. Just click next and wait for
the process to complete.
After the scan is finished, the full
structure of the reconstructed array
with all folders and files will be
displayed in the working window.
If necessary, you can use the preview
feature to check the contents of
documents, images, or other files.
Select the required files and folders
and click recovery.
Specify the save location for the
recovered data on a separate medium with
sufficient free space and confirm the
process by clicking recovery again.
When copying is complete, click finish.
As a result, all files will be recovered
and available for work in their usual
form.
This process guarantees data security,
allows you to return files even after
accidental deletion, and preserves the
ZFS file system structure without the
risk of damaging other data on the
disks.
If this material was useful, subscribe
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tips, and analyses of real cases related
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recovery after failures or deletion.
If you have any questions regarding the
steps performed, working with Hetman
RAID Recovery, or the specifics of using
TrueNAS, please leave them in the
comments. We will provide detailed
explanations and help you find the
optimal solution for your situation.
Thank you for watching. We wish you
stable system operation and reliable
preservation of your data.