Contents
Getting started
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Warning! The instruction below assumes you have basic technician skills for physical hard drives manipulations. In case you are not sure you can operate with physical hardware please consider of using professional data recovery service. |
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Attention! The article also describes device state after reset to factory defaults. This means if you are attempting to recover data from a failed device, it's recommended to read this article carefully because it provides valuable information for data recovery after device reset. |
Buffalo Technology provides wide range of Home and Small Office Network Attached Storage (NAS) solutions with simple to use LinkStation products. They provide efficient solution for shared network storage of valuable personal or business information.
Unfortunelly there are set of scenarios for data loss from this device:
Hard drive failure;
Electric or thermal shock may damage device motherboard;
Software failure or failed firmware update may reset device;
User mistake: some important information might be deleted by error.
How to recover the information? This will depend of NAS model and failure scenario:
LinkStation Mini, LinkStation Live, LinkStation Pro - the single-drive products:
There are only few simple steps:
Eject hard drive from the device;
Make sure hard drive works. Obviously it works in case data loss reason is simple files deletion or NAS re-initialization. If device failure reason is electric or thermal damage and drive does not work - contact your local data recovery laboratory for hard drive repair and data recovery;
If hard drive works, simply ;
Recover your information with any of or software products.
LinkStation Quad - or other QUAD-drive model:
Data recovery from this NAS is identical to .
The LinkStation Quad must be shut down and hard drive could be easily removed through the front panel. The default configuration and data layout for this product is similar to configuration for quad-drive TeraStation so please follow the guide fro more information.
LinkStation Duo (as well as Terastation Duo) - the DUAL-drive model:
The data loyout on these devices is simpler than on quad-drive models, however data recovery from this kind of devices raise even more issues then data recovery from more complex quad-drive models. The specifics of data recovery from LinkStation DUO and TeraStation DUO is described below.
Prepare Hardware
It only makes sense to start self-service data recovery in case of:
- Both hard drives are in good physical state;
- If configuration was RAID1 (mirror) - if at least one of drives is good.
Shut down the device. You can easily remove both drives through the front panel: simply open the door and eject the enclosures.
It makes sense to mark drives (Left/Right for Linkstation and Top/Bottom for Terastation) to return the drives back to the device later in the same order.
as described below and continue to data recovery.
Data Layout
The data layout is similar for all LinkStation and TeraStation products and is illustrated on picture below:
Pict. 1. The drives view in UFS Explorer version 5.
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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.
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Each drive has the same disk partitions structure. The purpose of partitions are:
- The boot firmware partition. This partition contains required files to boot embedded custom Linux OS (no user data here);
- The firmware partition. This partition contains embedded Linux system files such as executables, configurations etc. (no user data here);
- Swap partition. It is used by embedded Linux OS to extend RAM (memory swapping);
- 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;
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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. |
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RAID1 correct XFS file system will appear on data partition of each of NAS drives. For SPAN or RAID 0 first drive will contain 'SGI XFS' and second 'Unknown file system' on the data partition.
Diagnostics and data recovery
The common steps to diagnose the problems and rebuild NAS configuration on your PC are the following:
- Connect both drives to a PC
If you are sure configuration is mirror (RAID1), you may connect only one drive. In case of:
a) It does not show SGI XFS file system on data partition;
b) SGI XFS file system can not be read (read error);
c) You can not see some of files you saw on the device after data loss.
- it is required to connect both drive for further diagnostics.
- Check the reported file system type on data partitions
The result can be the following:
- Both drives contain SGI XFS file system on data partition (see Pict.1)
The device is configurad to RAID1 (mirror). The file system should be read on both drives. You should be able to recover all your data from any of the drives with any of or software products.
- Both drives contain Unknown file system (grey icon) on data partition (see Pict.1)
The file system is most likely destroyed or device worked as iSCSI target. This scenario requires professional service analysis and data recovery.
- One of drives contain SGI XFS and other Unknown file system (like shown on Pict.1 above)
The NAS is configured to RAID0 (default maximum capacity configuration) or Span. The drive with SGI XFS file system will be referred as 'first' and with Unknown file system as 'second'. Next step explains further analysis.
Next steps explain asymmetric configuration analysis. For RAID 1 (mirror) analysis is completed and you should be able to get your data from any of drives. If you can not recover your data, this requires professional service analysis and data recovery.
- Try to open SGI XFS file system on data partition of the first drive
Explaination of 'first' and 'second' drives is given above. There are two possible results you should receive:
- File system is opened and you can see "share" folder
- The NAS is most likely configured to SPAN. This also may appear for RAID0 with stripe size over 64KB, however on practice this scenario should not occur;
- File system can not be read
- The NAS is configured to RAID0.
More advanced verification is to run at least partial file system reconstruction scan over the drive. In case recovered files will have valid content - the configuration is JBOD (or RAID1 - see below); if contents is invalid - the configaration is RAID0.
- Verify RAID configuration
The SPAN (JBOD) verification includes:
- Check contents of "share" folder on the first drive;
- If there are files - check if all can be opened (e.g. with hex preview feature of UFS Explorer);
- In case all files can be opened - the second drive could be unused or be failed component of RAID1 - try to recover all the data from first drive.
- In case some files or folder are missing or some of files can not be opened - the configuration is SPAN.
The SPAN configuration on TeraStation and LinkStation products does not fit to data partition and can not be aligned without knowledge of XFS file system or professional service analysis.
The RAID0 verifications can be proceed wtih software even in trial mode. The steps include:
- Assemble RAID0 in UFS Explorer:
- Click 'Build virtual RAID array' tool button:
Pict. 2. Build RAID tool icon in UFS Explorer.
- This will display RAID builder dialog:
Pict. 3. Build Virtual RAID array tool in UFS Explorer.
- Switch 'RAID mode' to "RAID 0 (Stripe)";
- 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 second must be Unknown;
- Adjust stripe size if required (Buffalo products use default 64KB stripe size).
- Press 'Build'.
- The step above will produce new 'SoftRAID' virtual disk with single 'SGI XFS' file system. Try to open the file system. The possible results are:
- File system can not be read.
- Most likely stripe size is invalid. Open RAID configuration (as "Proersties" of the 'SoftRAID') and adjust the stripe size.
- File system can be read and "share" folder contains at least any of your data
- The RAID configuration is OK and you may continue to recovery.
- File system can be read and "share" folder is empty
- the NAS seems was reset to default maximum capcity configuration state.
- Analyse the reason and the status of RAID0
The data recovery from identified RAID1 requires simple operations using single drive and data recovery from SPAN in most cases require professional service assistance. The undisclosed scenario is default RAID0 configuration that is described below.
There are two main reasons for RAID0 to appear on the device:
- You have configured device to maximum speed/capacity;
- The device was reset to factory defaults.
For the first scenario you most likely will be able to find any of files or folders under "share" folder on SoftRAID (see Step 4). If any of files you are looking for are missing - you may simply scan the SoftRAID for lost information. In case you are attempting to recover deleted files, the recommended software is or with RAID Access Plugin - RAID Builder. The version 5 of software does not support deleted files recovery from XFS file system and is recommeded to use for data analysis and failed NAS recovery only.
The RAID0 may also appear due to device reset to factory defaults. The SoftRAID assebled at Step 4 in this case will contain new default file system and empty "share" folder (no user data). The further recovery will depend of original NAS configuration:
- The original configuration was RAID0 (stripe)
- in case previous configuation was "maximum speed and capacity" and drives were not swapped in NAS before reset (device reset due to hardware repair, software or firmware update, command from 'NAS Central' utility etc.) - the file system was formatted.
To recover your information you have run the "Data Recovery" scan with UFS Explorer with 'File system reonstruction' option enabled. It's not recommeded to enable other options (find deleted files, search by type) to save memory. For this scenario any of UFS Explorer software can be used.
If you swapped drives in NAS before device reset - you have to rebuild RAID as described at step 4 but in reverse drives orde. This will produce SoftRAID with 'Unknown' partition. To recover you data you will have to use or software products with RAID Access Plugin - RAID Builder.
- The original configuration was RAID1 (mirror)
- in case previous configuation was half of full capcity and was redundant, the original data was more damaged. It was written new XFS file system with different paramters so simple file system reconstruction will give wron results.
The recommended action is to use or and scan the second drive (with Unknown file system on the data partition). This should override effect of invalid XFS structures located on the first drive. If this does not provide any good result, it's recommended to request profesional data recovery services assistance.
- The original configuration was SPAN
- in this case the file systems are almost equal. To recover the data it's required to destroy invalid XFS superblocks produced with RAID0 format. After this RAID can be re-assebled as span and you may run file system reconstruction. On-disk structures modifications and span align will require knowledge of XFS file systems structures or professional data recovery assistance.
After device reset it destroys some of on-disk structures. This means some files, folders or file names could be lost permanently. It's recommended to analyse entire tree of "reconstructed file system" for files you are looking for. Some files and folder in this case may and will appear under "[Parent unknown]" virtual folder with "numbered" file/folder names.
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 .
Last update: 16.08.2010
