RAID Controller Failure on NAS Synology DiskStation DS3611xs: Data Recovery Approaches and Consequences

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 Synology 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 data redundancy techniques such as mirroring or replication enhance data availability and protect against loss on NAS Synology DiskStation DS3611xs devices?

Data redundancy techniques such as mirroring or replication can enhance data availability and protect against loss on NAS Synology DiskStation DS3611xs devices in the following ways:

1. Mirroring: Mirroring, also known as RAID 1, involves creating an exact copy of the data on multiple hard drives. In case one drive fails, the other drive(s) can continue to serve the data, ensuring high availability. On the DS3611xs, you can configure RAID 1 with two drives or use RAID 10 with multiple drives for better performance and redundancy.
2. Replication: Replication involves creating duplicate copies of data on separate NAS devices or remote locations. This ensures that even if one NAS device fails, the replicated data can be accessed from the backup device. Synology DiskStation DS3611xs supports various replication methods like Snapshot Replication, Shared Folder Sync, or Hyper Backup, allowing you to choose the most suitable method for your needs.
3. High Availability (HA): The DS3611xs supports High Availability, where two identical DiskStations work in an active-passive mode. The active DiskStation handles all data operations while the passive one remains in sync. If the active DiskStation fails, the passive one takes over seamlessly, minimizing downtime and ensuring continuous data availability.
4. Automatic Failover: With the High Availability feature, the DS3611xs can automatically detect a failure and switch to the passive DiskStation without manual intervention. This ensures that data remains accessible even during hardware or network failures, enhancing availability.
5. Snapshot Technology: Synology DiskStation DS3611xs supports snapshot technology, allowing you to create point-in-time copies of your data. Snapshots provide an additional layer of protection against accidental data deletion, ransomware attacks, or data corruption. In case of data loss or corruption, you can easily restore the data from a previous snapshot.

By implementing these data redundancy techniques, the Synology DiskStation DS3611xs devices can ensure high availability, reduce the risk of data loss, and provide quick recovery options in case of failures or disasters.

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

Although NAS DiskStation DS3611xs 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 Synology DiskStation DS3611xs. 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 Synology

DiskStation DS3611xs 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);

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 Synology DiskStation DS3611xs 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.

Comparison of software for RAID recovery