RAID Array Tips for Successful NAS Digiever DS-16336-RM Pro+ Data Recovery

Contents

• Why Regular Data Recovery Tools Can’t Restore Files from RAID
• Key Information About the NAS Digiever DS-16336-RM Pro+
• 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 Digiever 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 a NAS Digiever DS-16336-RM Pro+ device's caching policy impact data loss risks?

The caching policy of a NAS (Network Attached Storage) device like the Digiever DS-16336-RM Pro+ can impact data loss risks in several ways:

1. Write caching: NAS devices often use write caching to improve performance by temporarily storing write operations in cache memory before writing them to the underlying storage media. However, if power is suddenly lost or the system crashes before the cached data is written, there is a risk of data loss. To mitigate this risk, NAS devices usually have mechanisms like battery-backed cache or write-through caching, which ensure that data is written to the storage media before acknowledging the completion of a write operation.
2. Read caching: Read caching is used to improve read performance by storing frequently accessed data in cache memory. While read caching generally doesn't pose a significant risk of data loss, there is a possibility of data inconsistency if the cached data is outdated or becomes corrupted. NAS devices often employ techniques like cache coherence protocols or periodic cache refreshing to minimize this risk.
3. Cache synchronization: In NAS devices with multiple nodes or clustered configurations, cache synchronization becomes critical. If data modifications are made on one node and not immediately synchronized with the caches of other nodes, there is a risk of data inconsistency or loss during a failover or system recovery. NAS devices typically employ cache coherency protocols, like write-back or write-through mechanisms, to ensure data consistency across nodes.
4. Cache failure: Like any other hardware component, cache memory can also fail. If the cache memory of a NAS device fails, it may result in data loss or data corruption. To mitigate this risk, NAS devices often have redundant cache modules or mechanisms for cache mirroring, where data is simultaneously stored in multiple cache modules to ensure data availability even in case of cache failure.

It is important to note that while caching policies can impact the risk of data loss, they are just one aspect of a comprehensive data protection strategy. Other factors like RAID configurations, backup practices, and disaster recovery plans should also be considered to minimize the risk of data loss in a NAS device.

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

Although the NAS DS-16336-RM Pro+ 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 Digiever DS-16336-RM Pro+. 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 Digiever

DS-16336-RM Pro+ has 16 HDD slots, and it supports the following array types:

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

NAS supports:

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

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 Digiever DS-16336-RM Pro+ 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