- 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?
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.
Are there any known limitations or performance bottlenecks that can increase data loss risks for NAS Synology DiskStation DS620slim devices?
While Synology DiskStation DS620slim devices are generally reliable, there are a few known limitations and potential performance bottlenecks that can increase data loss risks:
- Limited drive capacity: The DS620slim supports up to six 2.5-inch SATA drives, which have smaller capacities compared to larger 3.5-inch drives. This limitation may lead to more frequent disk swaps or the use of smaller drives, increasing the risk of data loss due to drive failures.
- Limited RAM: The DS620slim comes with 2GB DDR4 memory, which may be insufficient for demanding workloads or multiple concurrent users. Insufficient RAM can result in slower performance and potential data loss if the system becomes overwhelmed.
- Network limitations: The DS620slim has a single Gigabit Ethernet port, which may limit the network throughput and performance, especially when multiple users are accessing the NAS simultaneously. This limitation can lead to slower data transfers and potential data loss if network congestion occurs.
- Limited expansion options: Unlike some other Synology models, the DS620slim has limited expansion capabilities. It does not support expansion units or additional RAM upgrades. This limitation may restrict scalability and potential performance improvements.
- RAID limitations: The DS620slim supports various RAID configurations, including RAID 0, 1, 5, 6, and 10. However, RAID 5 and 6 configurations have a higher risk of data loss during the rebuild process due to the larger capacity and longer rebuild times. Additionally, RAID configurations do not provide protection against data loss caused by accidental deletion or file corruption.
To mitigate these risks, it is important to regularly backup your data, use reliable drives, maintain a stable network environment, and consider upgrading to a higher-end Synology model with more robust hardware specifications if your requirements demand it.
How to take hard disks out of the NAS and connect them to a PC?
Although NAS DiskStation DS620slim 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:
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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.
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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.
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Make sure to mark each hard disk in accordance with how they were installed inside the NAS.
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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 DS620slim. 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.
DiskStation DS620slim has 6 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:
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Make sure that you have enough free space to save the image. The image file size usually equals the disk size.
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Select the disk in the main window, and choose from the menu Tools – Save Disk. You can select multiple disks to be saved.
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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.
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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 DS620slim 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
Product | Operating system | License type | RAID controller support | Supported file systems | Virtual RAID controller support | Data recovery from damaged RAID | File preview |
---|---|---|---|---|---|---|---|
Hetman RAID Recovery | Windows | Paid | Yes, over 100 controllers | FAT, NTFS, Ext2/3/4, HFS+ | Yes | Yes | Yes |
DiskInternals RAID Recovery | Windows | Paid | Yes, over 100 controllers | FAT, NTFS, Ext2/3/4, HFS+ | No | Yes | Yes |
R-Studio | Windows, Mac, Linux | Paid | Yes, over 200 controllers | FAT, NTFS, Ext2/3/4, HFS+ | Yes | Yes | Yes |
UFS Explorer RAID Recovery | Windows, Mac, Linux | Paid | Yes, over 1,000 controllers | FAT, NTFS, Ext2/3/4, HFS+ | Yes | Yes | Yes |
EaseUS Data Recovery | Windows | Paid | Yes, over 20 controllers | FAT, NTFS, Ext2/3/4, HFS+ | No | Yes | Yes |
ReclaiMe Free RAID Recovery | Windows | Free | Yes, over 100 controllers | FAT, NTFS, Ext2/3/4, HFS+ | Yes | Yes | Yes |