Buffalo RAID 5 array data recovery

Buffalo TeraStation RAID data recovery

In Blog, RAID Data Recovery, Server/RAID Array Recovery Case Study by Administrator

Four disk Buffalo TeraStation RAID array data recovery

During the autumn of 2015, CDR – Manchester Data Recovery Services – has received a total of five Buffalo TeraStations for data recovery. Pictured are four of these devices. All of these are Network Attached Storage (NAS) devices and have come from small businesses storing data for their employees.

Buffalo RAID 5 array data recovery

A ‘herd’ of Buffalo NAS RAID arrays. All failed with multiple HDD failure. Recovered by CDR during the autumn of 2015

RAID level

Of the five TeraStations received, three were configured in RAID 5, one in RAID 10, and one in RAID 0. Frequently the customers are not aware of what configuration was used, and during the work it is necessary to establish this. When a RAID device is received, particularly when there are multiple disk failures, it is not necessarily possible to establish what RAID level the device was configured immediately. This is why CDR provides an accurate fixed price RAID data recovery quotation in advance of receiving the device, which will cover all possibilities.

Multiple Disk Failure in RAID

Of the five TeraStations which had arrived to CDR during September and October, all had suffered multiple disk drive failure. In one case, whilst the customer was moving business premises, the TeraStation had suffered physical shock, which resulted in three of the four HDDs failing, including HDDs with mechanical failures (failure of the read-write heads). In the other cases, the HDDs had arrived with bad sectors (degraded media) and firmware failure. To start recovering data from the RAID array it is first necessary to recover data from each HDD individually by obtaining a full clone of the HDD. Use of hardware disk imaging equipment is essential for this. Once the failed HDDs have been imaged to working destination HDDs it is possible to establish the RAID configuration.

RAID 5 Buffalo TeraStation configuration

The configuration of RAID can vary significantly. It is determined by the type of hardware (or occasionally software) controller used on the device. For the reconstruction of RAID 5, the Buffalo TeraStations tend to have RAID configurations using the following:

  • RAID 5: Backwards Dynamic parity distribution
  • Large stripe size (256KB or greater)
  • Offset (start of RAID 5) approximately 7000 Mb into each HDD
  • Linux filesystem – XFS

Success

For all five RAID arrays it has been possible to make a good recovery of the data. As with all data recovery work conducted by CDR, a file listing is provided to the customer advance of any payment.

Information on the costs associated with such work can be found on CDR’s “RAID Array Prices and Quotations” page.