What to Do When Your NAS Thecus N7700SAS RAID Array Fails: Comprehensive Recovery Guide

Contents

• Why Regular Data Recovery Tools Can’t Restore Files from RAID
• Key Information About the NAS Thecus N7700SAS
• How to Remove Hard Disks from Your NAS and Connect Them to a PC
  • Step-by-Step Data Recovery with Hetman RAID Recovery
  • How to Safely Recover Data from Disk Images
  • Where Are the User’s Files Actually Stored?
  • RAID Recovery Software: Detailed Comparison

Why Regular Data Recovery Tools Can’t Restore Files from RAID

Conventional hard drives store user data by writing it sequentially across the disk surface, which means an entire file is typically located on a single drive. In contrast, when data is written to a RAID array, each file is split into multiple fragments. These fragments are then distributed and written in sequence across all the drives in the array. Depending on the configuration, fragment sizes can range from 2 KB to 2 MB, so every file is physically stored across several disks at once.

This approach significantly increases read and write performance — after all, writing two halves of a 1 GB file to two drives simultaneously is much faster than writing the full 1 GB to a single disk. However, this same mechanism makes file recovery far more complex.

Different RAID levels use different methods to distribute and protect data. On top of that, manufacturers like Thecus often add their own proprietary structures and variations. As a result, data can be written to disks in many different formats, and each requires a specific approach during recovery.

How can regular disk health monitoring and analysis help in preventing potential data loss on NAS Thecus N7700SAS devices?

Regular disk health monitoring and analysis can help in preventing potential data loss on NAS Thecus N7700SAS devices in the following ways:

1. Early detection of disk failures: By regularly monitoring the health of the disks, you can identify any signs of potential failures such as bad sectors, read/write errors, or abnormal temperature levels. This allows you to take proactive measures like replacing the failing disks before they completely fail and cause data loss.
2. RAID array maintenance: NAS devices like Thecus N7700SAS often use RAID configurations to provide data redundancy and protection against disk failures. Regular disk health monitoring helps in identifying any issues with individual disks in the RAID array. By replacing the failing disks promptly, you can ensure the integrity and availability of your data.
3. SMART monitoring: The Self-Monitoring, Analysis, and Reporting Technology (SMART) feature in hard drives provides detailed information about the drive's health and performance. By regularly analyzing the SMART data, you can identify any warning signs or anomalies that may indicate an impending disk failure. This enables you to take appropriate actions to prevent data loss.
4. Predictive failure analysis: Some disk monitoring tools offer predictive failure analysis, which uses historical data and statistical models to predict the likelihood of disk failures. By analyzing this data, you can identify disks that are more likely to fail in the near future and replace them proactively, minimizing the risk of data loss.
5. Data backup and recovery: Regular disk health monitoring can remind you to regularly backup your data and ensure that your backup systems are functioning properly. In case of a disk failure or data loss event, having up-to-date backups can significantly reduce the impact and recovery time.

Overall, regular disk health monitoring and analysis provide valuable insights into the condition of your NAS disks, allowing you to take preventive measures, maintain data integrity, and minimize the risk of potential data loss.

How to Remove Hard Disks from Your NAS and Connect Them to a PC

Although the NAS N7700SAS can be accessed over the network, you still need to remove its hard disks and connect them directly to a Windows PC. Only then can the recovery software properly scan and analyze the drives. Follow these steps:

1. Power off the NAS and disconnect it from the power source.

   WARNING! Before removing any drives, carefully read the device manual. Improper actions may damage both the NAS enclosure and the hard disks in the RAID array.

2. Remove the hard disks one by one, gently sliding each drive out of its slot. Remember that hard disks are highly sensitive: any impact or drop can cause serious physical damage.

3. Label each hard disk according to its position inside the NAS. The order of the drives is crucial for correct RAID reconstruction.

4. Connect the drives to your computer. In this video, we explain which ports you can use to connect hard disks and what to do if your PC does not have enough free connectors.

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   How to Order Remote Data Recovery

Step-by-Step Data Recovery with Hetman RAID Recovery

This program restores data from damaged RAID arrays and is fully compatible with Thecus N7700SAS. Each hard disk in the array contains technical metadata describing how files were written. When launched, Hetman RAID Recovery analyzes this metadata, automatically reconstructs the damaged array, and provides access to its contents. After that, you can browse the recovered disk and save your files. The program can also restore files that were accidentally deleted from the network drive.

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How to recover data from a Thecus

N7700SAS has 7 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• RAID 5;
• RAID 6;
• RAID 50;
• RAID 60;
• RAID 10;
• JBOD;

NAS supports:

• EXT3;
• EXT4;
• XFS;

How to Safely Recover Data from Disk Images

This utility allows you to create a complete copy of a disk and work with the disk image instead of the physical drive. This approach helps protect your data from:

• Overwriting during the recovery process;
• Additional data loss caused by bad sectors;
• User errors.

To create a disk image, follow these steps:

1. Ensure you have enough free space to store the image. Its size will typically match the size of the original disk.

2. In the main window, select the target disk and choose Tools - Save Disk. You can also select multiple disks if needed.

3. When the Image Creation Wizard opens, select whether you want to save the entire disk or only a specific region. Adjust the settings and click Next.

   

4. Choose the directory where the image will be saved. You may select any available disk connected to your PC or upload the image via FTP.

   

Where Are the User’s Files Actually Stored?

The Thecus N7700SAS 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.

RAID Recovery Software: Detailed Comparison