I am wondering how safe a hardware RAID configuration can be.
In case of a HDD failure, I just need to replace the damaged hard drive. What if the server motherboard crashes? Is it possible to get the HDDs and put them in a whole new server without loosing all the data?
In order words, is there any critical data stored into the RAID controller and is the configuration hardware dependent?
This is about on-board RAID controllers.
Best Answer
Repeating what Mark Henderson said on Server Fault:
I personally use hardware RAID and have not had to do this, but I have been considering moving my 2x2TB hard drives to NAS for the household to use. Even with what they said, I would still personally take a backup if possible of at least your most important files just in case. Its always better to be safe than sorry.
To answer the question of what happens if the controller fails and you want to move the hard drives over to the new controller. You need to import these foreign hard drives into the new system. RAID stores the configuration on both the disks and the controller.
The exact method of doing this will be down to a per controller basis, but it appears you want the hard drive in the same slot numbers they were in, and you want to have a data backup on standby in case it goes awry. If you can get an identical controller, this seems to help.
It is important to remember with RAID you want a backup to go along side it. RAID keeps you going in the event of a drive failure. Backups protect you when it goes catastrophically wrong (Or you need to recover that file you accidentally deleted.)