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How to: Recover data from 4-disk Buffalo TeraStation

Buffalo Technology provides a wide range of NAS solutions for Personal, Home and Small Office use. These solutions offer a space-efficient shared storage with access over a local network. Unfortunately, despite enhanced reliability of modern NAS solutions they still remain exposed to failures and data losses.

This article describes data recovery methods from popular 4-disk Buffalo TeraStation solution of Bufallo Technology using UFS Explorer RAID Recovery and is also applicable to LinkStation Quad NAS.

Contents

Getting started

Warning! The instructions below assume that you have basic skills to manipulate hard disk drives. Any physical damages to hard drives may cause permanent data loss. If you are not completely sure you can work with hardware, please, turn to data recovery laboratory.


The most common causes of data loss from NAS storages include:
  • Firmware or hardware failure;
  • Hard drive failure;
  • Faulty firmware update;
  • NAS re-configuration;
  • Accidental deletion of important information by user mistake.

Data recovery chances depend on embedded storage configuration and data loss causes:
  • RAID 5: The most widely-used. The data are distributed across the drives and are protected with parity. RAID5 ensures good operational speed and use of 3/4 of storage capacity. The data remain recoverable even without one drive.
  • RAID 10/0+1: Data are distributed across one pair of drives and are mirrored with the second pair of drives. RAID 10/0+1 ensures good operational speed, use of 1/2 of storage capacity and high reliability. The data remain recoverable after failure of one drive; if two drives fail recovery chances are about 67%.
  • RAID 0: Data are distributed across the drives. RAID0 ensures maximum operational speed and maximum use of storage capacity. Failure of one drive results in loss of all data.
  • JBOD: Data are spanned along all disks. This ensures full use of storage capacity and quite good performance. Failure of one drive results in loss of all data.
  • Multi-part storage: each drive has its own dedicated file system that is mounted under dedicated 'share' folder. Failure of one drive results in loss of 'share' folder on this disk.

In case of hardware failure, other than hard disk failure, firmware failure or faulty firmware update the data remain recoverable regardless of NAS configuration. NAS re-configuration usually causes partial data loss from previous configurations.

For efficient recovery from NAS storages SysDev Laboratories advise their UFS Explorer software. UFS Explorer RAID Recovery was specially designed to work with complex RAID systems. UFS Explorer Professional Recovery offers professional approach to data recovery process. These software have embedded tools for RAID recovery. Other UFS Explorer products work with RAID systems via plug-in modules. All the software employ powerful mechanisms to allow you to achieve maximum possible recovery result and are 100% reliable to guarantee complete safety of the data stored on your NAS. For more detailed information, please, go to http://www.ufsexplorer.com/products.php.



Prepare the hardware

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

  • All NAS hard drives are workable;
  • One drive failed – for RAID5 or RAID 10 (0+1) only;
  • Two drives failed – for RAID 10 (0+1) only.
For multi-part storage partial recovery after drive(s) failure is also possible.

As NAS devices don't provide low-level access to data you'll have to disassemble the storage and connect its hard drives to a recovery computer before you start data recovery. Please read HOW TO: Connect IDE/SATA drive to a recovery PC article for instructions. Mark drives order with paper stickers or soft ink marker.

Also prepare a safe storage where you will copy the recovered data to. Network drives or external USB drives are preferable.



Data Layout

4-disk Buffalo TeraStation and LinkStation Quad have the following data layout:


TeraStation Drives in UFS Explorer


Figure 1. NAS drives in UFS Explorer RAID Recovery.


Note:
  • Actual view will depend on software version and edition;
  • Actual drives sizes will depend on the NAS model;
  • Identified partitions will depend on the NAS model and software version and edition;
  • Extended partition (partition with sub-partitions) is a container and is not mentioned further on.

Each NAS drive has the same structure of the partitions:
  1. Boot firmware partition. This partition contains files to boot embedded custom Linux OS (no user data here);
  2. Firmware partition. This partition contains embedded Linux system files such as executables, configurations etc. (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 software RAID virtual device.

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


For multi-part storage or RAID1 valid XFS file system will appear on the data partition of each NAS drive. For SPAN or striped RAID (RAID0, RAID5, RAID10) some data partitions will display 'Raw partition' as they contain no valid file system start.



Data Recovery

Before you start data recovery make sure that the order of NAS drives is correct. Please refer to How to identify NAS drives order from XFS NAS article for instructions.

Multi-part storages and RAID1 configuration provides for data recovery without RAID reconstruction. XFS file system is detected on data partition of each drive. If the file system is not detected on RAID1 or multi-part storage you'll need to reconstruct the file system. To do this run "Data Recovery" scan enabling 'File system reconstruction' option with XFS file system.

To recover data from other RAID configurations follow the steps below:

Step 1. Run RAID builder dialog.

  1. Click 'Build RAID' button to invoke RAID Builder:

    Build RAID

    Figure 2. Build RAID tool icon in UFS Explorer.


  2. This will display RAID builder dialog:

    Builder dialog

    Figure 3. RAID Builder tool in UFS Explorer.




Step 2. Reconstruct RAID.

  • RAID 5:

    RAID 5 is usually a default RAID configuration for 4-disk Buffalo TeraStation and is offered as a default setting in UFS Explorer.

    To reconstruct RAID 5:

    1. Add data partitions of each NAS drive to the components list in the correct order. The first data partition will be SGI XFS, the others – Raw partitions;
    2. If one of the drives is missing, press 'Placeholder' button to substitute the missing drive. The placeholder takes the place of the missing drive following the drives order;
    3. Adjust stripe size, if required (Buffalo products use default 64KB stripe size);
    4. Press 'Build'.


  • RAID 0:

    RAID0 configuration provides for fast operations and maximum use of storage capacity.

    To reconstruct RAID0:

    1. Switch 'RAID mode' to 'RAID 0 (Stripe Set)';;
    2. Add data partitions of each NAS drive to the components list in the correct order. The first data partition will be SGI XFS, the others – Raw partitions;
    3. Adjust stripe size, if required (Buffalo products use default 64KB stripe size);
    4. Press 'Build'.


  • RAID 10:

    RAID10 configuration provides for fast operations, redundancy and use of half of the storage capacity.

    To reconstruct RAID10:

    1. Switch 'RAID mode' to 'RAID 0 (Stripe Set)';
    2. Add any of SGI XFS data partitions as the first, any of Raw data partitions as the second (use 2 partitions only);
    3. Adjust stripe size, if required (Buffalo products use default 64KB stripe size);
    4. Press 'Build'.


  • JBOD (span):

    JBOD is a non-redundant configuration that has quite good performance and provide for use of full storage capacity.

    To reconstruct JBOD:

    1. Switch 'RAID mode' to 'JBOD (Span)';
    2. Add data partitions of each drive to the components list in the correct order. The first data partition will be SGI XFS, the others – Raw partitions;
    3. Press 'Build'.

Usually, the size of a data partition doesn't fit to the size of JBOD component. Before you assemble JBOD you need to adjust the size of data partition manually. This operation requires detailed analysis and is not described in this article.


Step 3. File system detection.

After assembly RAID appears as a Virtual RAID in the storages tree. This storage will contain one partition with SGI XFS file system.

If the partition is displayed as Raw partition RAID was assembled with a wrong configuration or drives order. Please check the drives order.

Double-click the partition to open it in UFS Explorer. If the software warns about errors RAID was assembled with a wrong configuration. Please check stripe size and drives order.

If the file systems opens with default empty 'share' folder that doesn't contain your files, your device seems to have formatted the file system. In this case:

  1. Right-click partition and select 'Recover lost data' option;
  2. Select 'Recover file system type: SGI XFS file system';
  3. Select 'Enable IntelliRAW™ scan' for detailed files search;
  4. Run the scan;
  5. After the scan is completed, you will find all recovered files in UFS Explorer.


Note 1: If the data loss was caused by NAS failure, your data get accessible immediately after RAID assembly. No data recovery scan is required. If UFS Explorer warns about read errors or shows not all of your files, check RAID configuration.


Note 2: If the data loss was caused by accidental files deletion, all remaining data are displayed in UFS Explorer immediately after RAID assembly. To recover lost files select 'Recover lost data' in the context menu of SGI XFS partition of Virtual RAID in UFS Explorer.


Note 3: If the data loss was caused by NAS re-initialization, when UFS Explorer reads NAS correctly, but it contains only default folders, scan XFS file system for data recovery.


Note 4: If the data loss was caused by both NAS re-configuration and re-initialization, when you can see empty SGI XFS on RAID0 instead of expected files on RAID5, you may fail to recover lost data correctly. We advise to use professional data recovery services.





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 that you are capable of 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 commercial basis.




Last update: 10.04.2012