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Contents

• Getting started
• Prepare Hardware
• Data layout
• Data Recovery
• Final notes

Getting started


In the most common case Buffalo Terastation NAS failure or data loss occurs due to:

• Firmware or hardware failure;
• Single hard disk failure;
• Unsuccessful firmware update;
• NAS re-configuration.

Depending of embedded storage configuration it's possible to recover all or almost all user information from failed NAS. The NAS supports several storage modes (RAID and non-RAID configurations) which provide end-user with different data protection levels and different recovery chances after NAS failure:

• RAID 5: Most popular. Data is distributed across the drives and is protected with parity. It ensures good speed and 3/4 storage capacity. All data could be recovered even after single drive failure.
• RAID 10/0+1: Data is distributed across pair of drives and is mirrored with second pair of drives. It ensures good speed, 1/2 storage capacity and good protection. All data could be recovered after single drive failure; in case of two drives failure the data still could be recovered with 67% probability.
• RAID 0: Data is distributed across the drives. It ensures maximum speed and maximum storage capacity. Single drive failure causes all data loss.
• JBOD: Data is spanned along all disks. This ensures full storage capacity and fair performance. Single drive failure may cause all data loss.
• Multi-part storage: each drive has own dedicated file system that is mounted under dedicated 'share' folder. Single drive failure causes single 'share' folder loss.

In case of hardware failure (other than disk), firmware failure or unsuccessful firmware update the data in most cases is recoverable with any NAS configuration. NAS re-configuration usually causes partial data loss with any of previous configurations.

Please find all information related to your NAS configuration and proceed to next step: prepare hardware.

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Prepare Hardware

It only makes sense to start self-service data recovery in case of:

• All NAS hard drives are in good physical state (working);
• Single drive failed - if used RAID5 or RAID 10 (0+1) only;
• Two drives failed - for RAID 10 (0+1) only.

Partial recovery in case of drive(s) failure is also possible for multi-part storage.

Any type of data recovery from NAS will require direct connection of NAS drives to Windows recovery PC. Please read the how to connect drives to Windows PC guide. When you taking drives off NAS it's strongly recommended to mark drives order with either paper stickers on drives or by making notes on drive bodies with soft ink marker.

At this stage it is also recommended to connect the drive to copy data to (the preferred targets are network drives or external USB drives).

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Data Layout

For data recovery from Buffalo Terastation it's recommended to use UFS Explorer Professional Recovery software product. After all NAS drives are connected, run UFS Explorer. The data layout on disks is the following:





Pict. 1. The drives view in UFS Explorer.

The picture shows two different style of disk partitions: "extended" partitions (left) and "primary" partitions (right). Both styles may appear on Buffalo LinkStation or Buffalo TeraStation products.

Please note that:

• Actual view could depend of UFS Explorer version;
• Actual drives size will depend of NAS model;
• Identified partition types will depend of NAS model and UFS Explorer version;
• Extended partition (the partition with sub-partitions) is container and is not counted in further text of this guide.

Each drive has the same disk partitions structure. The purpose of partitions are:

1. The boot firmware partition. This partition contains required files to boot embedded custom Linux OS (no user data here);
2. The firmware partition. This partition contains embedded Linux system files such as executables, configurations etc. (no user data here);
3. Swap partition. It is used by embedded Linux OS to extend RAM (memory swapping);
4. Data (storage) partition. (indicated with red arrow). These partitions contain actual user files. For RAID configurations these partitions of each drive are combined into software RAID virtual device;

Other vendors/models notice: Depending of vendor and NAS model there could be from two and up to four partitions on each drive. It's easy to identify data partition as it is the largest partition (95..99% of full disk space) and it has no sub-partitions.

For multi-part storage or RAID1 correct XFS file system will appear on data partition of each of NAS drives. For span or RAID with stripes (RAID0, RAID5, RAID10) some of data partitions will show 'Unknown file system' as they do not contain valid file system start.

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Data Recovery

Please ensure drives order is correct. It's strongly recommended to make sure twice by using technique descibed in how to identify NAS drives order from XFS NAS guide.

For multi-part storage or RAID1 you may get data back without RAID reconstruction. The XFS file system will be detected on data partition of each drive. If file system is not detected on RAID1 or multi-part storage, use UFS Explorer Standard Recovery version 4 to reconstruct damaged file system (run data recovery over data partition and force XFS file system type).

For other RAID configuration, follow the steps below:

Step 1. Run RAID builder dialog.

1. Click 'Build virtual RAID array' tool button:
   
   
   
   Pict. 2. Build RAID tool icon in UFS Explorer.
   
   
2. In "Select RAID builder mode" dialog - select second mode: on disk partitions and press 'Next'.
   
   
   
   Pict. 3. Build RAID tool mode selection in UFS Explorer.
   
   
3. This will display RAID builder dialog:
   
   
   
   Pict. 4. Build Virtual RAID array tool in UFS Explorer.
   
   

Step 2. Specify RAID parameters.

• RAID 5:
  
  It is the default configuration of 4-disk Buffalo NAS products and it is default configuration in UFS Explorer. You have to:
  
  
  1. Add data partitions of each drive to 'include into RAID' list in correct order (indicated with red arrow on Pict.4). The first data partition will be SGI XFS, the others must be Unknown;
  2. If one of drives missing, press 'Add DPH>>' button to add 'Virtual disk placeholder' instead of missing drive. The placeholder must appear at correct place according to missing drive order position;
  3. Adjust stripe size if required (Buffalo products use default 64KB stripe size).
  4. Press 'Build'.
  
  
  
• RAID 0:
  
  The fast, maximum capacity configuration. The reconstruction steps include:
  
  
  1. Switch 'RAID mode' to "RAID 0 (Stripe)";
  2. Add data partitions of each drive to 'include into RAID' list in correct order (indicated with red arrow on Pict.4). The first data partition will be SGI XFS, the others must be Unknown;
  3. Adjust stripe size if required (Buffalo products use default 64KB stripe size).
  4. Press 'Build'.
  
  
  
• RAID 10:
  
  The fast, redundant, half-capacity configuration. The reconstruction steps include:
  
  
  1. Switch 'RAID mode' to "RAID 0 (Stripe)";
  2. Add any of SGI XFS data partitions as first, any of Unknown data partitions as second (use 2 partitions only);
  3. Adjust stripe size if required (Buffalo products use default 64KB stripe size).
  4. Press 'Build'.
  
  
  
• JBOD (span):
  
  The fair performance, non-redundant, full-capacity configuration. The reconstruction steps include:
  
  
  1. Switch 'RAID mode' to "JBOD (Span)";
  2. Add data partitions of each drive to 'include into RAID' list in correct order (indicated with red arrow on Pict.4). The first data partition will be SGI XFS, the others must be Unknown;
  3. Press 'Build'.
  
  
  
  In most cases data partition size does not match to JBOD component size. This means you have to adjust data partition size manually before assembling JBOD. This operation is subject of detailed analysis and is not described in this guide.
  
  
  

Step 3. Final file system detection.

After you pressed 'Build' button, the new virtual storage will appear immediately (default name is 'SoftRAID'). This storage must contain single partition with SGI XFS file system.

In case file system is shown as unknown, most likely you specified wrong RAID configuration (drives order). Please check drives order and try again.

Double-click the partition to open it in UFS Explorer. In case software shows errors, most likely this means wrong RAID configuration. It's recommended to check stripe size and drives order.

In case it shows only default empty '/share' folder without your files, this most likely means your device formatted the file system (this may occur after self-recovery after failure). In this case:

1. Right-click partition and choose 'Data recovery: Advanced scan';
2. Choose pre-set as 'File system reconstruction';
3. Run the scan;
4. After scan completed, you may all the recoverable information.

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Final notes

If you not sure you can recover data by yourself, it's strongly recommended to bring your NAS to specialized data recovery laboratory to avoid data loss.
In case you are working in data recovery but have difficulties with mass NAS analysis, you may commercially use SysDev Laboratories data recovery services.

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