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RAID Data Recovery

June 27th, 2010 | Author: man

RAID Data Recovery – Alandata Data Recovery

To be good at RAID data recovery you need a few characteristics:

  • You need to understand RAID thoroughly.?It has been said we “wrote” the book on RAID, as we wrote our own software to recover RAID.
  • Tremendous analyst, stubborn and determined. In RAID recovery, the critical step is the analyzing phase. In this phase we have to determine
  • How many drives makeup the array? What kind of array?
  • Whats the proper order? Which parity are the using left? right? symmetric?
  • Are there any unused hot spares? or partially rebuilt spares? stale spares?
  • Whats the blocksize of the stripe?
  • Has 1 drive been dead for a long time and its information is degraded?
  • Have any disks been swapped or re-built?
  • etc, etc, etc.
  • Tools. Good analysis tools are essential. CopyRAID features to allow us to look at the data and determine the configuration. Having written the code ourselves, we can re-write it to help solve difficult recoveries.. Like writing special code to look for certain things. We also write programs to combine data from good areas of multiple damaged disks.

About 90% of the RAID recoveries we receive come from other Data Recovery companies. That teaches you most recovery companies do not possess the required expertise to analyze and recover a RAID. Frequently we get the RAID after the other company has had it for a week and can’t figure it out.

Case study: RAID 1 – 2 x 160gb mirrored set: Recently another Data Recovery company brought in a RAID. The client reinitialized it, reformatted it and installed a new copy of Windows – overwriting 7 gigabytes of a 160 gigabytes RAID. The company that brought it to me was out of time – they had had it for 1 week, the customer was demanding it back and all they had been able to recover so far was some small file fragments. We scrutinized it, figured it out, and recovered it the very next day. They got back 99% of their data, with names and folders – just about perfect – despite their effort to wreck it.

Case study: RAID 5 – 4 x 1 terabyte. Data recovery company brought in a RAID 5 that they had for a few weeks with no luck. We scrutinized it. It appeared to be a RAID 5. We determined the order and parity, everything confirmed. We deraided to a new RAID array – but the files were all bad – nothing was lining up. We tried a few more copies using missing drive parity to regenerate the ‘lost’ data – still wasn’t working. Then after in-depth examination, we found it was a 3 drive raid with a spare – but the client (another data recovery company…) had rebuilt the RAID as a 4 drive, RAID 5. So it looked like a RAID 5, in sync with no parity errors. Normally, this would cause all kinds of damage. Lucky for the client, he rebuilt the spare so his data wasn’t damaged. He just devised a insidious puzzle for the data recovery technician.

 

The permutations and possibilities are endless. It requires experience, and patience to analyze all the data and figure out what went wrong, in what order and how to fix it. Liking puzzles is a requirement. puzzles anyone?

Some of our RAID recovery service highlights:

  • In 1998 we developed CopyRAID, our own internal RAID data recovery software utility.
  • We have utilized CopyRAID to recover thousands of RAIDS.
  • Recovered small 3 – 10 gigabyte RAIDS all the way up to huge 20 terabyte SAN arrays with 20 hard drives.
  • Recovered RAIDS running on dedicated RAID controllers, like Adaptec, Dell, HP, Lacie, Snap.
  • Recovered software RAIDS such as Windows Dynamic Disk or Linux and those found in NAS devices.
  • Recovered RAIDS from Novell, Linux, Unix, Mac, Windows.
  • RAID Data Recoveries for Ratheeon, IBM, New York Medical Center..
  • Recovered RAIDS after the larger nationwide recovery companies had tried and failed.
  • 90% of the RAIDS we receive are sent to us from Data Recovery companies who cannot recover the data (What does that tell yo?)

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