NAS Synology DiskStation DS411+II / DS411+ / DS411 / DS411slim / DS411j RAID Arrays: Data Recovery Tips for Component Wear

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.

Can implementing user quotas or permissions help prevent accidental data loss on NAS Synology DiskStation DS411+II / DS411+ / DS411 / DS411slim / DS411j devices?

Yes, implementing user quotas and permissions can help prevent accidental data loss on NAS Synology DiskStation devices, including DS411+II, DS411+, DS411, DS411slim, and DS411j.

User quotas allow you to limit the amount of storage space that each user can consume on the NAS. By setting quotas, you can prevent users from accidentally or intentionally filling up the storage with unnecessary or large files, thus ensuring that there is always enough space available for critical data.

Permissions, on the other hand, control the access rights of users to specific files and folders on the NAS. By assigning appropriate permissions, you can restrict users from modifying or deleting important files or folders, reducing the risk of accidental data loss. For example, you can set read-only access or deny delete permissions to certain folders containing critical data.

Additionally, Synology DiskStation devices offer advanced features such as file versioning and snapshot replication, which can further safeguard against accidental data loss. File versioning allows the NAS to keep multiple versions of a file, enabling you to restore previous versions in case of accidental modifications or deletions. Snapshot replication creates point-in-time copies of data, providing a way to recover files or folders to a previous state.

It is important to regularly back up your data from the NAS to an external storage device or a cloud backup service as an additional layer of protection against accidental data loss.

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

Although NAS DiskStation DS411+II / DS411+ / DS411 / DS411slim / DS411j 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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Restoring data with Hetman RAID Recovery

This program recovers data from damaged RAID arrays and is fully compatible with Synology DiskStation DS411+II / DS411+ / DS411 / DS411slim / DS411j. 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 DS411+II / DS411+ / DS411 / DS411slim / DS411j has 4 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 DS411+II / DS411+ / DS411 / DS411slim / DS411j 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