RAID arrays are the most comprehensive option for those who have large volumes of data and/or have data security in mind and/or are interested in high access speeds at the same time.
Different types of RAID are intended for different needs, for example, RAID 1 offers high security but -relatively- low speed, RAID 5 offers security but increased cost, RAID 6 offers excellent security but it's even more pricey, and RAID 0 offers nothing at all (except speed) and is not recommended by no means.
The most popular types of RAID are RAID 5 (which gives n+1 security, i.e. with the loss of a disk in the array there is no problem accessing the data) and RAID 10 (RAID 1+0, combines mirroring and striping) which offers security due to RAID 1 and speed due to RAID 0.
A specialized data recovery lab will follow these steps to recover data from a crashed RAID array:
- Reception of the RAID array and signing of the confidentiality agreement NDA
- Discussion with the customer, obtain crucial information regarding the conditions under which the failure occurred, the history of the disks life, and the needed data (type, location on the disk) that have to be recovered.
- Run a detailed diagnostic for each members of the array. The check includes the examination of the individual functions and components of the disk, such as the condition of the board, surfaces, read heads, etc.
- Inform the customer about the results and get required approval.
- Εκτέλεση της βασικής διαδικασίας ανάκτησης, ανάλογα με τη βλάβη. Για παράδειγμα, αν κάποιο μέλος της συστοιχίας παρουσιάζει βλάβη στις κεφαλές, τότε θα πρέπει να επιλεγούν προσεκτικά τα κατάλληλα ανταλλακτικά και να μπει στο Clean Room για αντικατάσταση των κεφαλών).
- Imaging of all members of the array
- Research and find the individual parameters of the array from all the clones that have been created (eg for a RAID 5 we need to find the stripe size, the order of the drives, the offset, the type of the RAID 5 (Left or Right, Synchronous or Asynchronous), any delay (for HP or Compaq servers) or any other 'exotic' settings it may have).
- Create a virtual array with all its members (from the clones) and apply the parameters discovered in the previous step
- Evaluation of the outcome and data extraction.
- Testing critical data (eg SQL database) for functionality.
- Inform client about final result and get approval.
- Copy the data to a new hard drive and deliver to the customer.