There are many reasons why this may have happened. You could have a faulty Raid controller, you could have a backplane issue

or you may have a firmware/Bios incompatability.

If you have upgraded your system board, raid controller, ESM to the latest levels it may be a controller problem.

Try going into the BIOS of the RAID controller and reconfiguring that array. Do not initialise the array

Save the config and hopefully you will see your data again.

 

If the PE2600 is still covered by warranty I suggest you place a call with Dell who should be able to diagnose/isolate your

problem