How to recover data from a RAID array with a dead controller? How to create a RAID 5EE storage system with an Adaptec ASR-6805T controller? What to do if one or several disks within the array break down? How to replace an inoperable drive? How to recover the lost information after a controller error? Read this article for extended explanations, and learn the sequence of steps you need to take if you want to solve any of these issues.
Compared with conventional storage devices, RAID arrays offer much more disk space for all your files and folders. Also, they guarantee data integrity and safe extraction of any materials you store there, even if one of the drives within the storage system fails. Despite the high reliability of such systems, though, important information sometimes gets damaged, lost or inaccessible.
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Losing important data is something that you can never predict. Though RAID 5 is considered a very reliable solution to store digital materials, still it doesn’t give you a 100% guaranteed protection against possible data loss. At any time, one or several disks may fail, and this is also true about the controller, or other hardware involved in the process. This situation renders the whole RAID system inoperable, and you will have to find a way to get your data back.
How to create a RAID 5EE system based on an Adaptec ASR-6805T controller
First of all, let’s explore the process of creating a RAID system, the important aspects to be considered when building it, and the settings required to make data recovery possible. Our RAID will consist of six disks working with the controller, Adaptec ASR-6805T.
In order to access the controller’s BIOS after hardware initialization, you should press the key shortcut Ctrl+A while the computer is booting.
In the menu, select Array Configuration Utility.
In the new window, you need to initialize the disks in order to tell the controller which of them will be used in the array. Find and open the line Initialize Drives.
Use the Space or Insert key to select each of the disks, and then press Enter.
As a result, you will see a notification warning you that information on all initialized disks will be erased. Enter Yes to confirm your choice and launch the initialization process.
After initialization, we can start creating the array. In the main menu, open Create Array.
In the next page, look at the left panel in the window Select drives to create Array to select the drives which will make up the RAID, and then press Enter.
Now it’s time to configure the array properties. The new page will contain important properties that should be memorized. You will need this information later when you try to recover data from the disks.
Specify the array type, its name and size, block size, caching settings and other properties. In our case, we performed all operations on a RAID 5EE based on an Adaptec hardware controller and including six drives 300 Gb each.
Now the RAID system has been created. It will take some more time to finish the building process, and soon you will be able to boot your computer and use the disk array to store your data safely.
In the next part of the article, we will find out how to replace a faulty drive and rebuild a damaged array.
How to replace a failed drive and rebuild a RAID array
At this stage, we are going to simulate a scenario when one of the drives fails. RAID 5 is designed in such a way that the whole array remains operable if one of the storage devices breaks down.
After a drive fails, the array becomes degraded, and while the computer is booting, you will see a message like this.
Before you take any action, it’s better to back up all important data. This is crucial because anything may happen during the array rebuilding process (one more disk may fail, the process may freeze, or there might be a hardware issue) and cause a total loss of data. Later on, we will explore what should be done in case of system errors or failures, but now we are about to look into the process of rebuilding the disk array.
Connect a new disk to the controller, turn on the computer, and open controller properties. To access then while the computer is booting, press the key shortcut Ctrl+A. In the window that opens, select Array Configuration Utility. Your first step is to initialize the new disk, so open Initialize Drives.
In the next page, select the new disk by pressing the Insert or Space key and hit Enter.
The operating system will show you a warning saying that one or several drives belong to an array and initialization will destroy the data. Make sure that you selected a new empty drive and type Yes.
Then type Yes again to agree that the data in this storage device will be erased.
Now the initialized drive should be added to the RAID. Open the menu line Manage Arrays, press the key shortcut CTRL+S and access the management page.
Use the Space or Insert key to select the new drive, and then hit Enter.
A new system notification appears. In the special field, type Yes to confirm.
After this sequence of steps, the rebuild process should start.
From now on, you can boot the server in normal mode and continue your work. A complete RAID rebuild is quite a long process and it depends on a number of things – the performance of your controller/drives, current controller load/disk load, etc. The time required to rebuild the array will be reduced, and the whole process will go faster if you don’t start using the array right after a new drive was added. If possible, let the controller finish the rebuilding process and only then start using the array the way you prefer.
By now, we have explored the situation when only one drive within the array failed. But what shall we do if several drives no longer work properly, or the controller is dead, or the operating system won’t boot after you added a new drive to the array?
This is when it’s better to use Hetman RAID Recovery.
This tool lets you recover data from crashed RAID systems or disks that were used in such array; it reads all the information about the controller, the motherboard, or the software used to create a disk array. Also, this product can rebuild the crashed RAID and it lets you copy all important information from there.
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