How can one recover data from a NAS device?

data recovery from nas with ufs explorer

NAS (Network-attached storage) is a handy technology enabling shared access to a general centralized storage. It may be available for several computers, workstations or any other devices featuring network connection capabilities. Being much smaller, less expensive and easier to maintain than traditional file servers, such systems can boast the same functionality and reliability. This has led to their wide popularity among both corporate and home users who rely on them to serve their data storage and backup needs. Still, like any device, NAS units are exposed to failures and outages resulting in the loss of crucial information. Moreover, unlike typical PCs or Macs, they usually don’t have inbuilt undelete functions. Recovering data from them though possible, requires taking into account the peculiarities of this very storage type.

Whilst some NAS boxes contain only one drive with a single volume, such devices are found very rarely even among ones oriented towards personal use. As a rule, NAS units are multi-disk storage systems, with their hard drives linked together with the help of the RAID technology, which also serves for increased performance and provides protection against drive failure. RAID 0, RAID 1 and RAID 5 are by far the most common layouts used in NAS. Yet, some manufacturers, like Drobo and Synology, provide their own developments in this regard, which open up new possibilities but at the same time, add significant complexity to the process of data recovery.

Hint: All the basic RAID concepts are described in the peculiarities of data organization on RAID. To learn more about particular NAS technologies, like Drobo BeyondRAID and Synology Hybrid RAID, please refer to the corresponding article.

In fact, NAS is not merely a digital storage, but a networked appliance with its own CPU and a customized Linux operating system. Such a device is plugged into a router with the help of an Ethernet cable, providing access to its files via network file sharing protocols (NFS, SMB, AFP, etc.), and cannot be connected directly to the PC via USB. Owing to the lack of low-level access to physical drives arising from the storage specifics and mediocre CPU characteristics of such devices, data recovery from NAS requires taking the drives out of the NAS box and connecting them to a computer.

There are also several other factors to be kept in mind before starting the procedure:

  • overwriting operations which may be performed by the user, system, TRIM command on SSDs or full format permanently destroy the data deleted or lost from the NAS drives;
  • encryption of NAS drives in most cases doesn’t hinder data recovery as long as the encryption key is available and the area on the storage containing critical decryption metadata is intact;
  • though the failure of one drive (RAID 3, RAID 4, RAID 5, RAID 7, etc.) or two drives (RAID 6, etc.) can be compensated by the system, the rest of the drives involved in the process must be in working order. If you assume any physical issues, contact a reliable data recovery center or clone the drive and work with its copy instead of the storage itself. Attempts to replace a failed drive and rebuild the array before data recovery may cause data overwriting.

Warning: Please familiarize yourself with the peculiarities of the imaging process for defective drives.

Recover data from NAS based on RAID of various complexity

If the critical files were lost from the NAS drives due to some kind of logical failure, like mistaken deletion, formatting, corruption or different software issues, the right data recovery instrument will be able to return the missing information. SysDev Laboratories offers UFS Explorer and Recovery Explorer  as effective software solutions that allow working with RAID of various levels and types, including standard RAID (RAID 0, RAID 1E, RAID 3, RAID 5, RAID 6, RAID 7, etc.), nested arrays (RAID level 10, 50, 60, 50E, etc.) and custom RAID layouts along with vendor-specific configurations, like Drobo BeyondRAID or Synology Hybrid RAID. The programs support most Linux-based file systems, including Ext, XFS and Btrfs, which are generally responsible for managing data on NAS volumes.

To restore files from NAS with the help of UFS Explorer RAID Recovery, you will need to do the following:

  1. Prepare a computer which will be used for data recovery. It is recommended to use a Windows PC, as it doesn’t support Linux file systems and won’t be able to write any data to the problem drives. Download and install the program onto it, ensuring that the currently running operating system matches the version of the program.

    Hint: Please refer to the article сovering the choice of the right OS for NAS recovery for more detailed information.

  2. Find a storage large enough to place all the recovered files. This may be any internal/external drive mounted in the OS or a network location.

  3. Turn the NAS hardware off and get the drives out of the box. Pay attention to the order of the drives and label them according to the bays they belong to.

    Hint: If you are not sure how to remove the NAS drives correctly, please, refer to the video tutorial.

  4. Power off the computer and connect all the removed NAS drives to it – the best option is to use SATA ports found on the motherboard. If the system doesn’t have enough vacant SATA connectors, it is possible to use USB to SATA adapters or disk enclosures, though the latter approach will considerably affect the speed of the process.

    Note: If you don't know how you can plug the disk into the motherboard of the computer or сonnect the drive externally using a USB to SATA/IDE adapter, please rely on the video tutorials.

  5. Start the computer and launch UFS Explorer RAID Recovery. If needed, change its parameters in the corresponding pane.

  6. If you’ve created disk images to use them instead of the physical drives, open all of the disk image files with the help of the "Image file or virtual disk" option from the "Open" main menu item.

    open nas drives images with image file or virtual disk option in ufs explorer

  7. Explore the list of connected devices in the left pane of the main screen:

    1. 7.1 If the RAID metadata wasn’t severely damaged, you will be able to find the assembled storage among the options in the list. It can usually be identified by the corresponding icon, RAID level and the number of the drives.

      select assembled raid in ufs explorer interface

    2. 7.2 In case the program didn’t reconstruct the RAID configuration, you can assemble it manually from the member drives/disk images.

      1. 7.2.1 Click "Build RAID" and add each component to RAID using the respective storage context menu option. For most NAS models the largest "data" partitions are to be chosen rather than entire drives: as a rule, such volumes have the same size on each drive and the same non-zero offset.

        add raid components manually in ufs explorer raid builder

      2. 7.2.2 If the array is in the degraded mode, add a placeholder to indicate the missing constituent using the respective tool from the toolbar.

        add placeholder for missing raid component in ufs explorer raid builder

      3. 7.2.3 Adjust the order of the drives using the arrow-like buttons from the toolbar and define the correct RAID configuration in the RAID parameters sheet.

        set virtual raid configuration in ufs explorer raid builder

      4. 7.2.4 When finished, press the "Build this RAID" button.

        build this raid button in ufs explorer raid builder

        Note: If you don’t know which RAID configuration your NAS is based on, refer to the NAS documentation. You may make any number of reconstruction attempts, as the software operates in the read-only mode without modifying any information on the source disks. For this use the "Edit RAID configuration" storage context menu option which will open the array in RAID Builder for revision.

        Note: The procedure may slightly differ if your NAS makes use of a specific RAID configuration instead of conventional RAID.

  8. Select the volume mounted under the assembled RAID and check its content. If the files seem damaged, this may signal that RAID parameters were defined incorrectly. Right-click the RAID storage in the left pane, choose "Edit RAID configuration" and try adjusting them. Press "Build this RAID" again upon completion.

    edit raid configuration option in ufs explorer

  9. To scan this volume for lost data use the respective button or the storage context menu option.

    three options to start selected raid volume scanning in ufs explorer

  10. Specify the desired scan parameters, press "Start scan" and wait for the process to end up.

    set parameters for selected raid partition scanning in ufs explorer

    Hint: More information about configuring the scan can be found in the instruction on scanning a drive with UFS Explorer.

  11. Examine the presented result. If the "Set up displaying of file status" function is turned on, circular icons will appear next to each file, representing their state. A green icon implies that a file is "good" and has a correct header; a red icon characterizes a severely damaged (zeroed) file; a gray icon may mean that a file was partly corrupted or its integrity cannot be checked in view of the format’s specifics. The deleted folders and files that have been recovered will be listed with red names. You may also sort the elements by name, date, size, employ quick or advanced search and preview images, videos, audio files or PDF documents.

    examine results of raid partition scan in ufs explorer

    Hint: The information provided in Evaluation and saving the results of data recovery may facilitate your work with the obtained folders and files.

  12. Click "Define permanent selection" and mark the items you would like to copy by putting ticks right next to them.

    select recovered raid files with ufs explorer define selection tool

  13. Press "Save selection" and select a destination folder for these files in the opened window.

    Hint: If you are going to save the recovered data to a network storage, please check the provided guide.

    Hint: The whole process is also demonstrated in the video guide to NAS recovery.

    save selected recovered raid files with ufs explorer save selection tool

Last update: August 09, 2022

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