NAS Synology RackStation RS2421RP+ / RS2421+ RAID Controller Failure: Causes, Recovery Steps, and Data Recovery Techniques

Contents

• Why Regular Data Recovery Tools Can’t Restore Files from RAID
• Key Information About the NAS Synology RackStation RS2421RP+ / RS2421+
• 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 Synology 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.

Can the use of specific data synchronization or replication mechanisms mitigate data loss risks for NAS Synology RackStation RS2421RP+ / RS2421+ devices?

Yes, the use of specific data synchronization or replication mechanisms can help mitigate data loss risks for NAS Synology RackStation RS2421RP+ / RS2421+ devices. Synology offers several built-in features and applications that can be utilized for data protection and redundancy.

1. Snapshot Replication: This feature allows you to take point-in-time snapshots of your data and replicate them to another Synology NAS or off-site server. Snapshots provide a quick and efficient way to restore data in case of accidental deletion, corruption, or ransomware attacks.
2. Hyper Backup: It enables you to back up data to various destinations, including local shared folders, external drives, remote Synology NAS, or cloud services like Amazon S3, Microsoft Azure, etc. Hyper Backup provides versioning and deduplication, ensuring efficient storage utilization and easy recovery of specific file versions.
3. RAID Configuration: The RS2421RP+ / RS2421+ supports various RAID configurations, such as RAID 1, RAID 5, RAID 6, and RAID 10. By configuring your NAS with RAID, you can achieve data redundancy and protection against drive failures. If a drive fails, the data can be rebuilt from the redundant information stored on other drives.
4. High Availability (HA): HA allows you to create a redundant system by pairing two RS2421RP+ / RS2421+ devices. In case of a hardware failure on one device, the other takes over seamlessly, ensuring uninterrupted access to your data.
5. Cloud Sync: This application synchronizes your NAS data with cloud storage services like Dropbox, Google Drive, or Microsoft OneDrive. By keeping a copy of your data in the cloud, you add an extra layer of protection against local data loss.

These mechanisms, when properly configured and used in combination, can significantly reduce the risk of data loss for NAS Synology RackStation RS2421RP+ / RS2421+ devices. However, it's important to regularly test and verify the backups and replication processes to ensure their effectiveness.

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

Although the NAS RackStation RS2421RP+ / RS2421+ 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 Synology RackStation RS2421RP+ / RS2421+. 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 Synology

RackStation RS2421RP+ / RS2421+ has 12 HDD slots, and it supports the following array types:

• Synology Hybrid RAID (SHR);
• RAID 6;
• RAID 5;
• RAID 10;
• RAID 1;
• RAID 0;
• Basic;
• JBOD;

NAS supports:

• Btrfs;
• EXT4;
• EXT3 (External Disk Only);
• FAT32 (External Disk Only);
• exFAT (External Disk Only);
• NTFS (External Disk Only);
• HFS+ (External Disk Read Only);

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 Synology RackStation RS2421RP+ / RS2421+ network-attached storage keeps DSM (DiskStation Manager) 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