RAID Disk File Access Without Online NAS Overland Storage SnapExpansion XSR: Practical Steps

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?
  • Restoring data with Hetman RAID Recovery
  • Safe recovery from disk images
  • Where are user’s files stored?
  • Comparison of software for RAID recovery

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 Overland Storage also introduce some modifications to this process, and that is why data can be written to hard disk in a wide variety of ways.

How can quality of service (QoS) settings impact data transfer reliability on NAS Overland Storage SnapExpansion XSR devices?

Quality of Service (QoS) settings can impact data transfer reliability on NAS Overland Storage SnapExpansion XSR devices in the following ways:

1. Bandwidth allocation: QoS settings allow you to allocate specific amounts of bandwidth to different applications or services. By prioritizing critical data transfers, you can ensure that they receive sufficient bandwidth, reducing the chance of congestion or delays that could impact reliability.
2. Traffic prioritization: QoS settings enable you to prioritize certain types of traffic over others. For example, you can prioritize real-time data transfers or applications that require low latency, ensuring their reliability by minimizing delays or interruptions caused by other less critical traffic.
3. Network congestion management: QoS settings help manage network congestion by ensuring that data transfers are given appropriate resources. By controlling the amount of bandwidth allocated to each transfer, QoS can prevent congestion-induced packet loss or delays, improving overall reliability.
4. Error correction and packet loss prevention: Some QoS mechanisms include error correction techniques or packet loss prevention mechanisms. These features can help maintain data transfer reliability by detecting and correcting errors or retransmitting lost packets, ensuring the integrity of the transferred data.
5. Traffic shaping: QoS settings can shape the traffic flow by limiting the rate at which data is transferred. This can prevent sudden bursts of traffic that may overload the network or cause congestion, leading to improved reliability by maintaining a more consistent and manageable data transfer rate.

Overall, QoS settings on NAS Overland Storage SnapExpansion XSR devices can significantly impact data transfer reliability by managing bandwidth allocation, prioritizing critical traffic, managing congestion, implementing error correction, and shaping traffic flow.

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

Although NAS SnapExpansion XSR 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:

1. 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.

2. 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.

3. Make sure to mark each hard disk in accordance with how they were installed inside the NAS.

4. 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 Overland Storage SnapExpansion XSR. 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 Overland Storage

SnapExpansion XSR has 12 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• RAID 5;
• RAID 6;
• RAID 50;
• RAID 60;
• JBOD;
• DynamicRAID;

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:

1. Make sure that you have enough free space to save the image. The image file size usually equals the disk size.

2. Select the disk in the main window, and choose from the menu Tools – Save Disk. You can select multiple disks to be saved.

3. 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.

   

4. 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 Overland Storage SnapExpansion XSR 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