Recovering Data from NAS Synology DiskStation DS1517+ / DS1517 RAID Arrays: Challenges of 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.

How can data fragmentation impact data availability and potential loss on NAS Synology DiskStation DS1517+ / DS1517 devices?

Data fragmentation can impact data availability and potential loss on NAS Synology DiskStation DS1517+ / DS1517 devices in the following ways:

1. Reduced Performance: Fragmented data can lead to decreased read and write speeds on the NAS device. This can result in slower access to files and applications, affecting overall productivity and user experience.
2. Increased Disk Wear: Fragmented data requires more disk operations to retrieve or write files, leading to increased wear and tear on the hard drives. This can potentially shorten the lifespan of the drives and increase the risk of data loss due to hardware failure.
3. Data Loss Risk: Fragmentation can increase the risk of data loss, especially in cases where the file system becomes corrupted or files are overwritten due to fragmented blocks of data. If the file system is unable to locate all the fragments of a file, it may result in permanent data loss.
4. Difficulty in Data Recovery: Fragmented data can make data recovery more challenging in case of accidental deletion or drive failure. Fragmented files may be scattered across different areas of the disk, making it harder to retrieve the complete file.
5. Reduced Storage Efficiency: Fragmentation can also impact storage efficiency on the NAS device. Fragmented data takes up more space on the disks as it is stored in non-contiguous blocks. This can lead to wasted disk space and reduce the overall storage capacity available for other files and applications.

To mitigate these risks, it is recommended to regularly defragment the data on NAS Synology DiskStation DS1517+ / DS1517 devices. Defragmentation rearranges fragmented data blocks, optimizing disk performance, and reducing the chances of data loss. Additionally, implementing regular backups and RAID configurations can provide an extra layer of protection against data loss.

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

Although NAS DiskStation DS1517+ / DS1517 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 DS1517+ / DS1517. 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 DS1517+ / DS1517 has 5 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 DS1517+ / DS1517 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