What is iSCSI and how does it work in the context of network storage?

iSCSI (Internet Small Computer System Interface) is a protocol used to transmit SCSI (Small Computer System Interface) commands over a network. It allows for the transport of block-level data between servers and storage devices over IP networks, enabling remote storage access and management.In the context of network storage, iSCSI works by encapsulating SCSI commands and data into IP packets, which can then be transmitted over an Ethernet network. This allows servers to access remote storage devices as if they were directly attached to the server's local bus.The iSCSI protocol involves two main components: the iSCSI initiator and the iSCSI target. The initiator is the client-side software or hardware that initiates the connection and sends SCSI commands to the target. The target, on the other hand, is the storage device that responds to the initiator's commands and provides access to the requested data.When an iSCSI connection is established, the initiator sends SCSI commands encapsulated in IP packets to the target. The target receives these packets, extracts the SCSI commands, and processes them as if they were coming from a locally attached storage device. The target then sends the requested data back to the initiator using IP packets.To ensure reliable and secure data transmission, iSCSI can utilize various network technologies such as TCP/IP for reliable delivery, and optionally, encryption and authentication mechanisms for data security.Overall, iSCSI provides a flexible and cost-effective solution for network storage, allowing organizations to leverage existing IP networks to access and manage storage resources remotely.

Can you explain the benefits and use cases of iSCSI in a NAS (Network Attached Storage) system?

iSCSI, or Internet Small Computer System Interface, is a protocol that enables the transmission of SCSI commands over IP networks. When it comes to a NAS system, iSCSI offers several benefits and use cases:Storage Consolidation: iSCSI allows multiple NAS devices to be consolidated into a single storage system. This helps in centralizing storage resources, simplifying management, and reducing hardware costs.Block-level Storage: Unlike traditional NAS that operates at the file level, iSCSI provides block-level storage access. It presents storage volumes as virtual disks, allowing servers to directly access and manage the storage as if it were a local disk. This makes it ideal for applications that require direct disk access, such as databases or virtualization platforms.Performance: iSCSI offers high-performance storage access as it leverages the speed and reliability of Ethernet networks. It can provide comparable performance to Fibre Channel (FC) without the need for dedicated FC infrastructure.Scalability: iSCSI allows for easy scalability by adding more storage devices to the NAS system. It supports the creation of multiple virtual disks, which can be expanded or shrunk as needed without disrupting the operation of the NAS.Data Protection: NAS systems utilizing iSCSI can benefit from various data protection mechanisms. For example, snapshots can be taken at the block level, allowing for efficient point-in-time copies of data. Additionally, iSCSI supports features like replication and mirroring, enabling data redundancy and disaster recovery.Virtualization: iSCSI is widely used in virtualization environments. It enables the creation of shared storage pools that can be accessed by multiple virtual machines, facilitating live migration, high availability, and centralized management of virtualized resources.Remote Storage: iSCSI allows for remote storage access over IP networks. This is particularly useful in scenarios where data needs to be accessed or shared across different locations or over the internet securely.Overall, iSCSI in a NAS system provides flexibility, performance, scalability, and data protection, making it suitable for various applications and environments, including enterprise storage, virtualization, and remote data access.

Does the NAS Digiever DS-4205 UHD support iSCSI protocol for storage connectivity? If yes, what are the specific features and capabilities related to iSCSI in this NAS model?

Yes, the Digiever DS-4205 UHD does support the iSCSI protocol for storage connectivity. Some of the specific features and capabilities related to iSCSI in this NAS model are:iSCSI Target: The DS-4205 UHD can function as an iSCSI target, allowing other devices on the network to connect to it and use it as a storage device.iSCSI LUN (Logical Unit Number): The NAS supports the creation of multiple iSCSI LUNs, which can be assigned to different devices or users, providing dedicated storage spaces.Thin Provisioning: The DS-4205 UHD supports thin provisioning for iSCSI LUNs. This feature allows the NAS to allocate storage space dynamically as needed, optimizing storage utilization.CHAP Authentication: The NAS supports CHAP (Challenge-Handshake Authentication Protocol) authentication for iSCSI connections. This ensures secure access to the iSCSI target by requiring a username and password.MPIO (Multipath Input/Output) Support: The DS-4205 UHD is compatible with MPIO, which allows multiple paths to be established between the NAS and the iSCSI initiator for increased reliability and performance.iSCSI Jumbo Frame Support: Jumbo frames can be enabled for iSCSI connections, which can improve data transfer efficiency by reducing the overhead associated with smaller frame sizes.These are some of the key features and capabilities related to iSCSI in the Digiever DS-4205 UHD NAS model.

How to recover data from Digiever DS-4205 UHD NAS

Name: How to recover data from a Digiever
Uploaded: 2023-08-24T16:59:16+03:00
Description: How to recover data from a Digiever

Is your network drive gone, and you are wondering what to do? Has a RAID system crashed, and your files are no longer accessible? Does your device display an error while booting? Have you accidentally rebuilt your RAID system? Are several hard disks out of order?

How to recover data from NAS Digiever DS-4205 UHD

Data Recovery Tool

Digiever DS-4205 UHD NAS Data Recovery in 2024

In this step-by-step tutorial, we’ll show you how to rebuild your RAID and recover data from DS-4205 UHD.

Contents

Why can’t ordinary software tools restore files from RAID?
How to take hard disks out of the NAS and connect them to a PC?

RAID Recovery™ 2.6

Recover data from damaged RAID arrays inaccessible from a computer.

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Why can’t ordinary software tools restore files from RAID?

Conventional hard disks keep user’s data by writing it to their surface in a consecutive way, and this is how an entire file is stored on a single hard disk. However, when data is written to a RAID system, a file is divided into several parts. Then these parts are written consecutively to all hard disks within such array. The size of such parts may range from 2 KB to 2 MB, so each file is stored on several hard disks at the same time.

Such approach helps to speed up read and write operations, and it is evident that saving two parts of a file having the size of 1 GB to two hard disks simultaneously is much faster than saving the same 1 GB of data to one hard disk. However, this peculiarity makes file recovery more complicated.

Various RAID levels store information in different ways. Additionally, manufacturers like Digiever also introduce some modifications to this process, and that is why data can be written to hard disk in a wide variety of ways.

Are there any known issues or limitations when using NAS Digiever DS-4205 UHD devices with virtualization platforms such as VMware or Hyper-V?

There are no specific known issues or limitations when using NAS Digiever DS-4205 UHD devices with virtualization platforms such as VMware or Hyper-V. However, it is always recommended to check the compatibility and system requirements of the specific virtualization platform you plan to use with the NAS device. Additionally, ensure that you have the necessary resources (CPU, RAM, storage) allocated to the virtual machines running on the virtualization platform to ensure optimal performance.

How to take hard disks out of the NAS and connect them to a PC?

Although NAS DS-4205 UHD can be accessed over the network, you still need to take the hard disks out of the storage device and connect them to a Windows computer. Only in this case will the software be able to scan them properly. Here is what you should do:

Turn off the storage and disconnect it from the power supply.

WARNING! Before you start taking hard disks out of your NAS device, read the manual carefully. Incorrect actions may damage your network-attached storage and/or the hard disks within the RAID system.
Take the hard disks out of the NAS one by one, carefully removing them from their slots. Remember that the disks are extremely vulnerable: hitting or dropping them may result in serious physical damage.
Make sure to mark each hard disk in accordance with how they were installed inside the NAS.
Remove the hard disks and connect them to the computer. In this video, we have explored what ports are used to connect hard disks, and what to do if there are not enough ports or connectors.

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How to Order Remote Data Recovery

Restoring data with Hetman RAID Recovery

This program recovers data from damaged RAID arrays and is fully compatible with Digiever DS-4205 UHD. The hard disks that make up the RAID contain technical information about the algorithm used to save files. When launched, Hetman RAID Recovery reads this information and puts the damaged array together. Then you can open the disk and save your files. Also, you can recover the files accidentally deleted from the network drive.

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How to recover data from a Digiever

DS-4205 UHD has 4 HDD slots, and it supports the following array types:

RAID 0;
RAID 1;
RAID 5;
RAID 6;
JBOD;

NAS supports:

exFAT, VFAT, FAT 12 / 16 / 32;
NTFS / ReFS;
APFS / HFS+;
Ext2 / 3 / 4 / ReiserFS / XFS / UFS / ZFS / Btrfs;
VMFS / HikvisionFS;

Safe recovery from disk images

This utility lets you save an entire copy of the disk to file and then work with this image instead of the actual disk. Such feature helps to protect data on the disk from:

Overwriting during the recovery process;
Loss resulting from bad sectors;
User mistakes.

To create an image, do the following:

Make sure that you have enough free space to save the image. The image file size usually equals the disk size.
Select the disk in the main window, and choose from the menu Tools – Save Disk. You can select multiple disks to be saved.
When the image creation wizard starts, you can choose to save the entire disk or select only a part of it. Specify the parameters and click Next.
At this stage, you need to choose a directory where to save the image. Choose any disk connected to this PC, or save the image by FTP.

Where are user’s files stored?

The Digiever DS-4205 UHD network-attached storage keeps OS Linux operating system files on a separate RAID 1 (mirrored) array. Usually, all NAS systems create several volumes on every hard disk, and the first of them takes up to 2 Gb of space. This is where operating system files are stored. Other volumes are united into a RAID array where user’s data is written.

Comparison of software for RAID recovery

Product	Operating system	License type	RAID controller support	Supported file systems	Virtual RAID controller support	Data recovery from damaged RAID	File preview
Hetman RAID Recovery	Windows	Paid	Yes, over 100 controllers	FAT, NTFS, Ext2/3/4, HFS+	Yes	Yes	Yes
DiskInternals RAID Recovery	Windows	Paid	Yes, over 100 controllers	FAT, NTFS, Ext2/3/4, HFS+	No	Yes	Yes
R-Studio	Windows, Mac, Linux	Paid	Yes, over 200 controllers	FAT, NTFS, Ext2/3/4, HFS+	Yes	Yes	Yes
UFS Explorer RAID Recovery	Windows, Mac, Linux	Paid	Yes, over 1,000 controllers	FAT, NTFS, Ext2/3/4, HFS+	Yes	Yes	Yes
EaseUS Data Recovery	Windows	Paid	Yes, over 20 controllers	FAT, NTFS, Ext2/3/4, HFS+	No	Yes	Yes
ReclaiMe Free RAID Recovery	Windows	Free	Yes, over 100 controllers	FAT, NTFS, Ext2/3/4, HFS+	Yes	Yes	Yes

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We will be happy to answer your questions!

Comments (3)

Hetman Software: Data Recovery 9.08.2022 12:31 #

If you want to ask a question about data recovery, from NAS DS-4205 UHD, feel free to leave a comment!

Reply
Allen Trimble 24.08.2023 15:57 #

Are there any specific software solutions for data recovery from NAS Digiever DS-4205 UHD devices with S.M.A.R.T. errors?

Reply
- Hetman Software 24.08.2023 16:59 #
  There are several software solutions available for data recovery from NAS Digiever DS-4205 UHD devices with S.M.A.R.T. errors. Some popular options include:
  EaseUS Data Recovery Wizard: It is a comprehensive data recovery software that supports NAS devices. It can recover data from various storage media, including NAS devices with S.M.A.R.T. errors.
  Stellar Data Recovery: This software is known for its powerful recovery capabilities. It can recover data from NAS devices, including Digiever DS-4205 UHD, even in case of S.M.A.R.T. errors.
  R-Studio: It is a professional data recovery software that supports NAS devices. R-Studio can recover data from Digiever DS-4205 UHD NAS devices with S.M.A.R.T. errors and other issues.
  GetDataBack: This software is designed specifically for data recovery from various storage devices, including NAS devices. It has a user-friendly interface and can recover data from NAS devices with S.M.A.R.T. errors effectively.
  It is important to note that data recovery from NAS devices with S.M.A.R.T. errors can be challenging, and there is no guarantee of 100% success. It is recommended to consult a professional data recovery service if the data is critical and valuable.
  Reply

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Updated:
24.08.2023 16:59

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Author: Vladimir Artiukh, Technical Writer

Vladimir Artiukh is a technical writer for Hetman Software, as well as the voice and face of their English-speaking YouTube channel, Hetman Software: Data Recovery for Windows. He handles tutorials, how-tos, and detailed reviews on how the company’s tools work with all kinds of data storage devices.

Editor: Oleg Afonin, Technical Writer

Oleg Afonin is an expert in mobile forensics, data recovery and computer systems. He often attends large data security conferences, and writes several blogs for such resources as xaker.ru, Elcomsoft and Habr. In addition to his online activities, Oleg’s articles are also published in professional magazines. Also, Oleg Afonin is the co-author of a well-known book, Mobile Forensics - Advanced Investigative Strategies.

Questions and answers

What is iSCSI and how does it work in the context of network storage?

iSCSI (Internet Small Computer System Interface) is a protocol used to transmit SCSI (Small Computer System Interface) commands over a network. It allows for the transport of block-level data between servers and storage devices over IP networks, enabling remote storage access and management.
In the context of network storage, iSCSI works by encapsulating SCSI commands and data into IP packets, which can then be transmitted over an Ethernet network. This allows servers to access remote storage devices as if they were directly attached to the server's local bus.
The iSCSI protocol involves two main components: the iSCSI initiator and the iSCSI target. The initiator is the client-side software or hardware that initiates the connection and sends SCSI commands to the target. The target, on the other hand, is the storage device that responds to the initiator's commands and provides access to the requested data.
When an iSCSI connection is established, the initiator sends SCSI commands encapsulated in IP packets to the target. The target receives these packets, extracts the SCSI commands, and processes them as if they were coming from a locally attached storage device. The target then sends the requested data back to the initiator using IP packets.
To ensure reliable and secure data transmission, iSCSI can utilize various network technologies such as TCP/IP for reliable delivery, and optionally, encryption and authentication mechanisms for data security.
Overall, iSCSI provides a flexible and cost-effective solution for network storage, allowing organizations to leverage existing IP networks to access and manage storage resources remotely.
Can you explain the benefits and use cases of iSCSI in a NAS (Network Attached Storage) system?
iSCSI, or Internet Small Computer System Interface, is a protocol that enables the transmission of SCSI commands over IP networks. When it comes to a NAS system, iSCSI offers several benefits and use cases:
1. Storage Consolidation: iSCSI allows multiple NAS devices to be consolidated into a single storage system. This helps in centralizing storage resources, simplifying management, and reducing hardware costs.
2. Block-level Storage: Unlike traditional NAS that operates at the file level, iSCSI provides block-level storage access. It presents storage volumes as virtual disks, allowing servers to directly access and manage the storage as if it were a local disk. This makes it ideal for applications that require direct disk access, such as databases or virtualization platforms.
3. Performance: iSCSI offers high-performance storage access as it leverages the speed and reliability of Ethernet networks. It can provide comparable performance to Fibre Channel (FC) without the need for dedicated FC infrastructure.
4. Scalability: iSCSI allows for easy scalability by adding more storage devices to the NAS system. It supports the creation of multiple virtual disks, which can be expanded or shrunk as needed without disrupting the operation of the NAS.
5. Data Protection: NAS systems utilizing iSCSI can benefit from various data protection mechanisms. For example, snapshots can be taken at the block level, allowing for efficient point-in-time copies of data. Additionally, iSCSI supports features like replication and mirroring, enabling data redundancy and disaster recovery.
6. Virtualization: iSCSI is widely used in virtualization environments. It enables the creation of shared storage pools that can be accessed by multiple virtual machines, facilitating live migration, high availability, and centralized management of virtualized resources.
7. Remote Storage: iSCSI allows for remote storage access over IP networks. This is particularly useful in scenarios where data needs to be accessed or shared across different locations or over the internet securely.
Overall, iSCSI in a NAS system provides flexibility, performance, scalability, and data protection, making it suitable for various applications and environments, including enterprise storage, virtualization, and remote data access.
Does the NAS Digiever DS-4205 UHD support iSCSI protocol for storage connectivity? If yes, what are the specific features and capabilities related to iSCSI in this NAS model?
Yes, the Digiever DS-4205 UHD does support the iSCSI protocol for storage connectivity. Some of the specific features and capabilities related to iSCSI in this NAS model are:
1. iSCSI Target: The DS-4205 UHD can function as an iSCSI target, allowing other devices on the network to connect to it and use it as a storage device.
2. iSCSI LUN (Logical Unit Number): The NAS supports the creation of multiple iSCSI LUNs, which can be assigned to different devices or users, providing dedicated storage spaces.
3. Thin Provisioning: The DS-4205 UHD supports thin provisioning for iSCSI LUNs. This feature allows the NAS to allocate storage space dynamically as needed, optimizing storage utilization.
4. CHAP Authentication: The NAS supports CHAP (Challenge-Handshake Authentication Protocol) authentication for iSCSI connections. This ensures secure access to the iSCSI target by requiring a username and password.
5. MPIO (Multipath Input/Output) Support: The DS-4205 UHD is compatible with MPIO, which allows multiple paths to be established between the NAS and the iSCSI initiator for increased reliability and performance.
6. iSCSI Jumbo Frame Support: Jumbo frames can be enabled for iSCSI connections, which can improve data transfer efficiency by reducing the overhead associated with smaller frame sizes.
These are some of the key features and capabilities related to iSCSI in the Digiever DS-4205 UHD NAS model.