Here's an interesting question and advice post from UK hard drive recovery experts Data Clinic regarding the subject of RAID data recovery. Now, it you didn't know, 'RAID data recovery' is the process of retrieving information from large computer storage
systems that have stopped working and therefore access to the files and folders on them has been lost. Retrieving the data from these large systems is a complex task as using the RAID topology,
the data held on them is divided equally by the number of hard disks in that system.
Question: I have a CalDigit element tower consisting of 4 hard drives, each is 1 TB formatted as one array raid 0. The Raid tower is connected to MacPro 2010 over mini-SAS cable, and the raid FILE SYSTEM IS MAC HFS+. The problem when i want to copy folder or file from raid to another local drive the copy process get stuck. I used RaidSheild a utility provided by calDigit to check the raid system and it say's one of the drives is not healthy.
And after the copying process get stuck the Raid volume can be accessed and i need to restart the system.
Answer: A 4 drive system running RAID 0 means that all the data held is split evenly across the 4 disks. On the plus side this means that data access is extremely quick but on the downside it means that failure of just 1 of the 4 disks will bring the whole system down. There's another interesting page on the Data Clinic site about the different kinds of hard drive failure - it's worth looking at this page to familiarise yourself with the various faults that may have befallen the hard drive in the Caldigit system.
The problem of recovering the data from the system will also be compounded by the HFS+ filesystem. As HFS+ is a journaled filesystem it means that it is extremely efficient in storing and managing data. Because of this it's very difficult rescuing data from this filesystem. HFS+ data recovery is best taken on a case by case basis, and rather than offer any advice myself, I recommend that you contact Data Clinic direct on 0871 977 2525.