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How to: Recover data from LinkStation and TeraStation Duo

Buffalo Technology provides a wide range of NAS solutions for personal, home and small office use. These devices offer space-efficient shared data storage with access over a local network. Unfortunately, despite enhanced reliability of modern Network Attached Storages, they still remain exposed to failures and data loss.

This article describes methods of data recovery from popular LinkStation and TeraStation Duo NAS solutions of Bufallo Technology using UFS Explorer RAID Recovery.


Getting started

Warning! The instructions below assume that you have basic skills of manipulating hard drives. Any physical damages to the storage media may cause permanent data loss. If you are not completely sure about your competence in working with hardware, please, turn to professional data recovery services.

Attention! This article contains details about the state of NAS after its resetting to factory defaults. Please read the article carefully for information about data recovery from a failed device after its resetting.

The most common causes of data loss from NAS include:

  • Hard drive failures;
  • Electrical damage or overheating of the storage;
  • Software failures or faulty firmware updates;
  • Accidental deletion of important information due to user mistakes.

Data recovery chances from NAS depend on the NAS model and the causes of data loss.

As NAS devices don't provide low-level access to data, you have to disassemble the storage and connect its hard drives to a computer before starting data recovery. Preparation steps include:

  1. Eject the hard drive from the device;
  2. Make sure that the hard drive is in the working state. If data loss was caused by a logical failure such as NAS re-initialization or just accidental file deletion, hard drives should remain intact. In case of any physical damage caused by, for example, electrical issues or overheating, as a rule, hard drives fail and data recovery is possible only after physical repair of the device. Bring your NAS to a specialized data recovery laboratory to avoid irreversible data loss;
  3. Connect the operable drive to a PC for recovery (as described in HOW TO: Connect IDE/SATA drive to a PC for recovery;
  4. Recover the lost information with any of the UFS Explorer Standard Recovery or Raise Data Recovery – XFS Support software products.

For efficient data recovery from NAS SysDev Laboratories advise their UFS Explorer software. UFS Explorer RAID Recovery is specially created to work with complex RAID systems. UFS Explorer Professional Recovery offers professional approach to the process of data recovery. This software features embedded tools for data recovery from RAID. Other UFS Explorer products work with RAID systems via plug-in modules. Each of the software solutions applies powerful mechanisms allowing you to achieve maximum recovery result and is 100% reliable, guaranteeing complete safety of the data stored on your NAS. For more detailed information please visit http://www.ufsexplorer.com/products.php.

Preparing Hardware

Note: Do-it-yourself data recovery makes sense only when:

  • Both hard drives are operable;
  • For RAID1 (mirror) – at least one of the drives is operable.

To prepare the hard drives for data recovery follow these steps:

  1. Shut down your NAS;
  2. Remove the drives through the front panel: open the door and eject the enclosures;
  3. Mark the drives (Left/Right for Linkstation and Top/Bottom for Terastation) to be able to re-assemble the device in the same order;
  4. Connect the drives to a PC.

When the NAS drives are successfully connected to a PC, you can start data recovery.

Data Layout

LinkStation and TeraStation have equal data layout:

Drives in UFS Explorer

Figure 1. NAS drives in UFS Explorer RAID Recovery.

Note:

  • The actual view depends on the software version and edition;
  • The actual sizes of the drives depend on the NAS model;
  • Identified partitions depend on the NAS model and the software version and edition;
  • The extended partition (a partition with sub-partitions) is a container and will not be mentioned further on.

Each NAS drive has the same partition structure:

  1. Boot firmware partition. This partition contains files necessary to boot embedded custom Linux OS (no user data is stored here);
  2. Firmware partition. This partition contains system files of the embedded Linux operating system such as executables, configurations, etc. (there is no user data here);
  3. Swap partition. This partition is used by embedded Linux OS to extend RAM (memory swapping);
  4. Data (storage) partition.This partition contains user files. For RAID configurations data partitions of each drive are combined into a software RAID virtual device.

Note: Depending on the retailer and the model NAS can contain from two and up to four partitions on each drive. Data partition is the largest one (takes up 95-99% of the entire disk space) and has no sub-partitions.

For RAID1 a valid XFS file system appears on the data partition of each NAS drive. For SPAN or RAID0 the first drive contains 'SGI XFS' on the data partition and the second one contains 'Raw partition'.

Diagnostics and data recovery

To diagnose and virtually rebuild your NAS configuration follow these steps:

Step 1. Connect both drives to a PC.

For the mirror RAID1 configuration you may connect one of the drives. In cases when
a) the drive doesn't show the SGI XFS file system on the data partition;
b) the SGI XFS file system is unreadable (reports read error);
c) you can't find some of the files available on the device after data loss.
– connect both drives for further diagnostics.

Step 2. Check the file system on data partitions

You will get one of the following results:

  • Both drives contain the SGI XFS file system on data partitions (see Fig.1)
    NAS is configured to RAID1 (mirror). The file system is readable on both drives. Data recovery is possible from any of the drives.
  • Both drives contain RAW partitions indicated with a gray icon (see Fig.1)
    The file system seems to be destroyed or NAS worked as iSCSI target. In this case your NAS requires professional data analysis and data recovery services.
  • One of drives contains SGI XFS and the other one – a RAW partition (see Fig.1)
    NAS was configured to RAID0 (the default configuration) or SPAN. The drive with the SGI XFS file system will be referred to as 'first' and the one with a RAW partition – as 'second'. Explanations as to further analysis you will find in Step 3.

After analysis you can start data recovery from any of the RAID1 drives. If you fail to recover your data, please, use professional data analysis and data recovery services.

Step 3. Open the SGI XFS file system on the data partition of the first drive

One of the following results may occur:

  • The file system is opened and you can see the "share" folder:
    NAS must have been configured to SPAN. In rare cases this result appears for RAID0 with the stripe size over 64 KB;
  • The file system is unreadable:
    NAS was configured to RAID0.

If you run a scan for at least partial file system reconstruction, you'll get a more precise result. If the recovered files have valid contents, it is a JBOD or RAID1 configuration, if file contents are invalid, this is RAID0.

Step 4. Verify the RAID configuration

For SPAN (JBOD):

  • Check the contents of the "share" folder on the first drive;
  • If the folder contains files, all of them can be opened using the hexadecimal preview tool of UFS Explorer;
  • If all files can be opened, the second drive can be an unused or a failed component of RAID1. Try to recover the data from the first drive;
  • If the files or folders are missing or some files cannot be opened, this is a SPAN

The SPAN configuration on TeraStation and LinkStation products doesn't fit to the data partition and cannot be aligned without the knowledge of the XFS file system or professional analysis.

For RAID0:

Assemble RAID0 in UFS Explorer:

Click the 'Build RAID' button to invoke RAID Builder:

Build RAID

Figure 2. Build RAID tool icon in UFS Explorer.

Builder dialog

Figure 3. RAID Builder tool in UFS Explorer.

After this:

  • Switch the 'RAID mode' to 'RAID0 (Stripe)';
  • Add data partitions of each drive to the list of the components following the drives order;
  • Adjust the stripe size if required (Buffalo products use the default 64 KB stripe size);
  • Press 'Build'.

When you assemble virtual RAID0, it will appear as a new storage with the SGI XFS file system in the tree of storages. If you open this file system, you will get one of the following results:

  1. The file system is unreadable:
    The stripe size is invalid. Open the RAID configuration and adjust the stripe size.
  2. The file system is readable and the "share" folder contains at least some of your data:
    the RAID configuration was successfully assembled and you can proceed to data recovery.
  3. The file system is readable but the "share" folder is empty:
    your NAS storage seems to be reset to the default configuration state.

Step 5. Analyze the reason for RAID0 emergence and assess the chances for recovery

The RAID1 configuration allows for data recovery from one of its drives. The SPAN configuration requires professional assistance of a data recovery specialist. The RAID0 configuration requires analysis and reconstruction.

The reasons for RAID0 emergence on your NAS storage include:

  • You have configured your NAS device to maximum speed/capacity;
  • The device was reset to factory defaults.

NAS re-configuration. After re-configuration of NAS storage the lost data remains recoverable. You should assemble the storage as described in the instructions of Step 4. All good files emerge in the 'share' folder of the Virtual RAID. If you don't find the files, scan the Virtual RAID for lost information.

NAS resetting. After virtual re-assembling of NAS storage as described in Step 4 Virtual RAID will display a new default file system and contain an empty 'share' folder. The chances for recovery depend on the original NAS configuration:

  • Original RAID0 (stripe set)
    • If the previous configuration was set as "maximum speed and capacity" and the drives weren't swapped before resetting, the file system of NAS was formatted. To recover the lost information run 'Data Recovery' scan enabling the 'File system reconstruction' option.
    • If the drives were swapped before NAS resetting, rebuild RAID as described in Step 4 but with the reverse order of drives. As a result you will get Virtual RAID with a RAW To recover the lost information run 'Data Recovery' scan enabling the 'File system reconstruction' option.
  • Original RAID1 (mirror)If the previous configuration was with half of full capacity and the redundant data sustained more serious damage as a new XFS file system was written with different parameters. Ordinary file system reconstruction cannot give expected results.

    Scan the second drive of NAS storage, the one with a RAW data partition. If this doesn't provide any positive result, it's recommended to use professional data recovery services.
  • Original SPANThe file systems remain almost equal. To recover the data destroy invalid XFS superblocks produced with the RAID0 format. After this re-assemble RAID as SPAN and run file system reconstruction. Note that modification of disk structures and span aligning require knowledge of the XFS file system structures or professional data recovery assistance.

    NAS resetting destroys some of on-disk structures possibly resulting in some files, folders or file names permanent loss. It's recommended to analyze the entire tree of the "reconstructed file system" for files you are looking for. Some files and folders can appear under the "[Parent unknown]" virtual folder with numbers in file/folder names.

Final notes

In case of any physical damages it's strongly recommended to bring your NAS to a specialized data recovery laboratory in order to avoid data loss.

If you feel unsure about conducting data recovery operations from your NAS by yourself or not confident about RAID configuration in your NAS, feel free to use professional services provided by SysDev Laboratories.

For data recovery professionals SysDev Laboratories offer expert NAS storage analysis on a commercial basis.

Last update: 05.07.2018