Gone are the days when RAID technology, short for Redundant Array of Inexpensive Disks, used mostly by large enterprises. Today, even regular home users use RAID arrays for storing their data, which means they’re affected by RAID data loss. Fortunately, there are now free RAID data recovery tools that make it easy to address it without advanced technical skills. Let’s see how one such tool, Disk Drill, works and how it stacks up against other recovery methods.
RAID stands up for Redundant Array of Inexpensive Disks, and it’s a data storage virtualization technology that makes it possible to combine several physical drives into a large logical unit. With this technology, users can achieve more storage capacity at high speeds and enjoy benefits such as redundancy and fault tolerance.
Fault tolerance implies the ability of a system to continue functioning as expected even when one or more hard drives fail or otherwise develop an error (fault). Data is copied across multiple hard drives and in the event of a disk failure data loss is avoided. Furthermore, with more hard drives combined the overall system benefits from increased efficiency and heightened performance.
RAID was originally developed for servers to create large storage at lower costs and quickly became popular among hobbyists and home users for many applications including personal DIY cloud storage and home media centers.
One popular non-standard configuration is RAID 10, which typically consists of two RAID 1 groups for data redundancy which are then used to create RAID 0 for improved performance.
RAID 0, 1, 5
The specific properties of the logical unit depend on which RAID configuration (level) you choose, such as RAID 0, RAID 1, or RAID 5. Besides these standardized RAID configurations, there are many non-standard levels, most of which were created by companies selling all kinds of proprietary RAID products to meet the needs of their customers.
What Are the Benefits of Using RAID?
Why would you want to create a RAID array when you can store files on the individual drives instead? Because RAID arrays offer two important benefits:
Let’s say you want to store a 1,000 MB large file on a hard drive whose maximum write speed is just 100 MB/s. In such case, it would take 10 seconds for the data transfer operation to finish. But if you equally distributed the same file across ten 100 MB/s hard drives, then you could theoretically save it in just 1 second because each hard drive would have to store just 100 MB, and that’s basically where the performance-enhancing benefit of RAID arrays comes from.
RAID is a versatile technology, and it can also be configured for data redundancy. For example, you can create a RAID array consisting of just two hard drives and configure it so that new data is mirrored on each drive. Should something happen with one of the two drives, the other one will still contain full copies of your files, making it easy to recover data from the RAID without any loss whatsoever.
Some RAID configurations provide improved performance, others provide data redundancy, but you can also enjoy both at the same time—it all depends on how many hard drives you have and how much of their total storage capacity you’re willing to sacrifice.
What Is RAID Recovery?
Just because some of the most popular RAID configurations, such as RAID 1 and RAID 5, offer significantly improved reliability compared with non-RAID configurations involving individual physical disks or multiple physical disks merely concatenated together into a single logical disk, doesn’t mean that RAID data recovery isn’t a topic of great interest.
There are many RAID users who need to recover data from RAID 0 arrays, which provide no data redundancy whatsoever. Such recovery attempts can be tricky, to say the least, because a single failed hard drive can be enough for critical bits of data to be lost forever. Your data recovery chances are much higher when performing data recovery on RAID 5 and RAID 1 arrays, for example, because of their baked-in data redundancy.
Just like when trying to solve any other data loss problem, time is an important factor when recovering files from RAID arrays. The sooner you begin the recovery process, the lower the chance of accidentally overwriting the lost files will be. Of course, you also need to use reliable RAID recovery software, such as Disk Drill.
When Is RAID Data Recovery Needed?
RAID data recovery is needed in many different situations, ranging from relatively minor to serious.
A RAID array doesn’t stop users from making unfortunate mistakes, so it shouldn’t come as a surprise that accidental deletion is a leading cause of RAID data loss. Because deleted files don’t immediately disappear from the array on which they were stored, their recovery is usually possible if started soon enough.
Due to software bugs and unpredictable physical and logical storage device errors, data can become corrupted and impossible to access unless the corruption is addressed first.
Certain strains of malware are so dangerous that they can make large quantities of files disappear in an instant regardless of which RAID configuration is used. Data recovery software can be a true lifesaver when it comes to dealing with the fallout of malware attacks.
When one or more disks in a RAID array become physically damaged, RAID recovery software is of limited use. Usually, the affected disks have to be sent to professionals for repair, which may not always be possible—it all depends on the extent of the damage.
Not all files that are overwritten by files with the same names are gone for good. In many cases, the new files are actually stored elsewhere on the RAID array, so now physical overwriting takes place, making the original files recoverable using the right software.
Formatting gone wrong
Formatting is incredibly destructive, and there’s a lot of potential for it having a catastrophic ending unless you’re careful and think twice before moving forward with it. Fortunately, data recovery attempts tend to have good outcomes when it comes to freshly formatted drives.
How to Recover Data from RAID Hard Drives
Disk Drill is a versatile data recovery software application capable of addressing a wide range of data loss situations and recovering over 300 file formats.
While it doesn’t have the ability to reconstruct RAID arrays, it can easily recover data from individual drives using its sophisticated data recovery algorithms. Here’s how to perform Windows RAID recovery using Disk Drill:
Connect one of the RAID drives to your computer
Disk Drill works best when used to recover data from individual hard drives that make up the RAID array. If you haven’t done so already, connect one of the RAID drives to your computer.
An external HDD dock makes this incredibly easy, especially if you have a laptop, but you can choose any approach you want. As long as your computer can recognize the hard drive and communicate with it, you will be able to begin the recovery process.
Download and install Disk Drill
Next, you need to download Disk Drill and install it on your system drive (not the RAID drive you want to recover). Disk Drill can be downloaded for free and used to preview an unlimited number of files.
Scan the connected drive
Once you have Disk Drill installed on your system, you can go ahead and launch it. You will be presented with a list of available storage devices, and the RAID drive should be among them. Select it and click Search for lost data. Wait for Disk Drill to complete the scan process.
Recover lost files
Go through the scan results and look for your lost files. Disk Drill lets you preview files before you recover them, and it automatically estimates the recovery chances of each file. To recover selected files, simply click the Recover button and tell Disk Drill where you want to place the recovered files.
Repeat from the first step
Now, repeat the previous steps for all remaining RAID drives until you’ve recovered all lost data.
Recover Data from a Variety of RAID Levels
Disk Drill can recover files from RAID configurations commonly used by home and enterprise users alike. Just know that you might need to scan the drives individually instead of as a single RAID.
RAID 0, RAID 1, RAID 0+1, RAID 1E, Microsoft RAID, MS Storage Spaces
RAID 5, RAID 50, RAID 5EE, RAID 5R, Apple RAID, Linux RAID
Tested with Popular RAID Manufacturers
A to F
ASUSTOR Data Recovery, Citrix Data Recovery, Citrix Data Recovery, Dell Compellent, Drobo Data Recovery, Equallogic Data Recovery
G to O
IBM Storwize, MS Hyper-V Data Recovery, NetApp Data Recovery, Novell RAID Data Recovery
P to Z
QNAP Data Recovery, SNAP Server Recovery, Sun Data Recovery
Common Causes of RAID Failure
RAID systems are generally considered a reliable and safe option for managing and accessing data. However, occasionally they are susceptible to failure just as other hardware devices and this may lead to catastrophic loss of data. The consequences are much more severe if important files were not previously backed up. Remember that RAID is not an alternative for backup, and even the most secure RAID array configurations can still fail. With this in mind, it’s imperative to continuously backup your data. RAID may fail due to several reasons, a few of which include:
RAID controller failure
A RAID controller may fail due to a disastrous power surge that can knock out the NVRAM, corrupt your hard drive partitions or damage the boot memory rendering it impossible to boot or access your data.
Power supply issues
From power surges to power outages to hardware issues, there are many potential power supply issues, and they can all cause RAID failure by damaging the controller itself or resulting in extensive logical damage.
Hard drive problems
Failure of a hard drive in an array may leave your array prone to future disk failure leading to system deterioration. Continued running of the array with degraded drives further increases the odds of suffering an even worse array failure.
Failure to rebuild
When a RAID drive is replaced and RAID rebuild errors occur, this may hinder you from accessing your files or even the entire RAID array.
The host machine of your RAID arrays may crash or fail, leading to corruption of your RAID controllers and rendering your data inaccessible.
Loss of RAID configuration settings
When RAID configuration settings become lost, an entire RAID array can become inaccessible, which is why it’s extremely important to be careful when upgrading RAID software.
Data Protection Capabilities
In addition to its impressive RAID recovery capabilities, Disk Drill also comes with useful data protection capabilities that can further decrease the likelihood of you losing important files. Best of all Disk Drill’s data protection capabilities are included as free extracts, providing as much value as many standalone software applications costing more than Disk Drill itself.
Recovery Vault can protect your files by saving the associated metadata (filename, file location, etc.), making it easier to recover them when they become deleted or disappear because of corruption, malware, or some other factor.
What to Do When Experiencing a RAID Failure
So now that you’ve suffered a RAID failure, what are the next steps to take? You’ll need to attempt RAID recovery to get back your data. Generally, the safest step at this point is to stop using the array and assess the severity of the damage to your RAID array. While it is generally recommended that you repair and replace the array as needed, recovery may also be an option.
Rebuild the RAID array
When you rebuild a RAID array, you replace a failing part with a working one. In most cases, the failing part that needs to be replaced is a hard drive, but it can also be the RAID controller.
When replacing a RAID drive, you need to determine which drive is failing and then replace it with an identical one. The rebuild process itself will then depend on your RAID controller and configuration. When replacing the RAID controller itself, it’s paramount to swap it for the same exact make and model.
Reconnect individual drives
Sometimes, the simplest fixes are the most effective ones. You certainly wouldn’t be the first person in the world to spend an entire day troubleshooting a problematic RAID array only to discover that a single SATA or power cable has been loose the entire time. That’s why we recommend you check all cables early on.
Repair the file system by running CHKDSK
The humble CHKDKS utility can verify the file system integrity of a volume and fix logical file system errors that prevent files from being accessible. Since this tool is one of core system utilities in Windows, it would be a shame not to give it a try.
All you need to do is enter the following command in Command Prompt:
Read S.M.A.R.T. data to detect bad drives
Modern hard drives support a technology called S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology). This technology can tell you a lot about the health of the drives that make up your RAID array, helping you spot a possible imminent drive failure.
Because Windows doesn’t come with an easy-to-use S.M.A.R.T. data tool, we recommend you a third-party software application like Disk Drill instead.
Use data recovery software
Data recovery software can be used to recover data from a failed RAID array that doesn’t function properly anymore. When choosing data recovery software, pay attention to its data recovery performance, usability, and price.
Disk Drill is a fantastic choice because it can recognize all commonly used Windows, macOS, and Linux file system and recover hundreds of file formats from them using multiple data recovery methods.
Genuinely, my past experiences have been exceptional with Disk Drill. I was able to rebuild multiple drives and recover several “lost” partitions following a freak accident. In Austin, TX we had a fire, nothing huge, but it happened to burn right through several houses in Steiner Ranch (including ours). Obviously, the fire took out every electronic device along with all our belongings but somehow my server wasn’t damaged to the point of no return as I was able to restore the aforementioned drives and partitions.