A Rundown on RAIDS and RAID Recovery Services

The Data Rescue Center’s RAID recovery service is professional, affordable, and secure. The technicians in-house specialize in both RAID Data Recovery and Server Data Recovery. We recover RAIDs and Servers with any type of configuration including Virtual Servers and Network RAIDs. Our lab offers the latest, most advanced equipment for hard drive recovery on RAID arrays. In this post, we’ll try to answer any questions you may have about RAID data recovery, including defining the different types of RAID systems, why your RAID could fail, and what to do when that happens.

What Does RAID Mean?

RAID is an acronym that stands for Redundant Array of Independent Disks. A RAID system is made of two or more hard drives connected together to create data mirroring or striping, depending on the RAID. The array is formed by attaching the disks to a hardware drive controller. The combination of multiple disks allows for redundant information storage. A RAID server in a striped array will perform faster, while a RAID in mirrored array will be slower.

What Is Mirroring?

Disk mirroring is the replication of data onto separate hard drives. Disk are known to be an unreliable component of computer systems. This technique allows a system to replicate and maintain multiple copies of the data across multiple hard drives. In the event of a disaster, the server can continue to access data from secondary sources.

What Is Striping?

Striping data refers to segmenting sequential data onto multiple storage devices in a continuous pattern. Striping accesses data faster because it comes from multiple sources. However, failure of one disk in a striping pattern causes a corruption of the full data set. This disadvantage can be overcome by parity blocks requiring additional storage.

What Is Parity?

Parity are blocks of redundant data distributed across the drives. This means when new information is written, the parity code is “striped” across all the disks in the set. This allows the RAID to rebuild the data if a drive failure occurs. Parity allows for redundancy.

What Is the Purpose of a RAID Array?

The Random Array of Independent Disks can be customized for performance, for reliability, and for storage. The server can store data files from multiple users, with more hard drives to process writing and retrieving requests. RAID arrays can hold large quantities of complementary data, to provide data redundancy. This stores multiple copies of the same file, ensuring data integrity in the event of a failure.

Specific RAID servers can be for strictly computing power, such as those used in gaming or scientific computing. The RAID server does this by reading information from multiple disks simultaneously. These high processing servers exist to crunch raw data, rather than save the information reliably.

What Are the Important Types of RAID Servers, and What Are They Used For?

The Data Rescue Center sees a majority of RAID 0, 1, 5, and 10 configurations, while the specialists here can also recover from RAID 2, 3, 4, and 50. There are custom and homemade configurations, including JBOD (just a bunch of disks), MAID (massive array of idle drives), and Spanned drives. Nested RAIDs refers to hybrid RAID systems, which combine two or more standard arrays for more redundancy or performance.

• RAID 0 – striping

• RAID 1 – mirroring

• RAID 5 – striping with parity

• RAID 6 – striping with double parity

• RAID 10 – combining mirroring and striping

RAID 0 is designed for faster computer performance by distributing data across multiple drives, allowing for faster read and write purposes. However, RAID 0 has no fault tolerance in the event of a hard drive failure. A single disk failure can take down the whole RAID. This model has no redundant sectors.

RAID 1 system is a mirrored hard drive that writes the data onto two locations. They are equal collaborators writing the same information onto two copies. RAID 1 systems provide redundant information storage, but sacrifice speed for this purpose. This is because read and write performance is equal to the speed of the slowest disk. The RAID 1 system allows for fault tolerance through mirrored redundancy. This means if one hard drive goes down, the server can continue with the other copy. This will give you time to copy the old hard drive onto a new hard drive, and reinsert it into the server again.

RAID 5 works by storing data on two disks while providing the combination of the two plus parity bits onto a third disk. If one disk fails, the system can continue. If two disks fail, RAID recovery is required. The RAID 5 system requires 3 or more disks to run. Since data is read from multiple disks, the RAID 5 system increases performance. Because the data and parity information is stored on separate disks, this provides redundancy protection and fault tolerance.

What Is the RAID Recovery Process?

The Data Rescue Center follows a set of protocols in recovering failed RAID systems. Every hard drive entered into the facility undergoes a cloning. This ensures data redundancy and prevents further deterioration of the drive. Then, our trained technicians make an initial examination to figure out the exact root of the problem. The recovery specialists extract all the available data from the hard drives, and figure out how to assemble the data again.

The recovery process for RAID systems relies on several key information factors. Each hard drive in the array needs to be correctly labeled in the position of the array. The type and model of the RAID system design is necessary to understand the data construction. Then, the Data Rescue Center has to know whether you attempted to rebuild or re-execute the hard drives yourself.

If you have any questions about the RAID recovery process, please call 1-877-501-4949 to speak with a RAID and Server recovery specialist. Or, visit the Data Rescue Center website under RAID Data Recovery.

What Can I Do When One Disk or Multiple Disks on My RAID System Fails?

Make sure you have a functional and recent backup of your RAID. If you have a backup of your hard drives, load that onto a disk image and re-insert that into your RAID. If you don’t have a backup, be careful, the situation is now critical and very sensitive. Mistakes that happen can result in total data loss.

The first thing to do when attempting any recovery is to clone every single drive in the RAID. When removing the array members from the array, you MUST label all of the hard drives, disk caddies, and bays of the enclosure. You must ensure that the disks are removed and returned to the same bay. If an array member is mounted in an incorrect bay, the data will be corrupted during the rebuild process. The best thing to do is label all of the hard drives, and record all of the information about your RAID system.

If only one drive failed, you can insert a new drive into the RAID and click rebuild. The RAID will rebuild the new hard drive from the parity blocks on the others. Perform the rebuild process and, if all goes well, your array will be back online. If you have issues cloning any of the array members, contact The Data Rescue Center to determine the best course of action.

If more than one drive fails in a RAID system without further redundancy, at this point, you will need either data recovery software or RAID recovery specialists. They will attempt to recover all available data and rebuild the information again.

Are RAID Systems Necessary?

RAID systems are the most reliable way to handle massive quantities of data. Several RAID configurations allow businesses to continue operations when failure occurs until it is possible to shutdown the system for repairs. Striped RAID systems allow processes that require lots of computing power, like video editing or animation.

The RAID system is not a substitute for standard hard drive backup procedures. RAID data redundancy isn’t safe from malware, theft, or natural disasters. But RAIDs are a protection against hardware failures.

We understand the stressful situation that happens when a RAID array goes down. This pressure can create situations where mistakes happen. If you don’t have a recent, functional backup, it’s best to take these steps to ensure the data’s safety, even if that means a loss in productivity. Rushing the process can result in total data loss and maybe job/business loss. It’s better to be safe than sorry.

Can My Company’s IT Staff Handle RAID Data Recovery?

That’s a tricky question to answer because it depends on several factors: the amount of training in data recovery the staff has, and the recovery equipment that is available to them. When physical drive failure is the problem, a cleanroom environment is needed to remove the contaminants in the atmosphere. Airborne contaminants like dust can enter the drive case and further damage the delicate components. All of the drives in a RAID array may need to be opened when recovering data. Irreparable damage to one or more drives could render the entire array unrecoverable.

Data recovery from RAID systems is a complex process. You have to identify whether the issue is a hardware or software problem. If the problem is hardware related, the connecting parts and hard drives of the RAID system need to be analyzed. If the problem is due to software errors, you can try out the free demo of Data Rescue. Coming from our sister company, Prosoft Engineering, Data Rescue specializes in finding corrupt or erased data. If Data Rescue can’t find the information, and there are no physical issues or other warnings, then the Data Rescue Center won’t be able to help you.

What Are the Weaknesses of RAID Systems?

There are some latent deficiencies in the RAID system. Because the structural components are in the same environmental conditions, the statistic likelihood of multiple drives crashing is much higher. This leads to correlated failures due to mechanical issues.

RAID systems are particularly vulnerable to data structure errors known as UREs (unrecoverable drive errors) during the hard drive rebuild process. The parity blocks that ensure correct data alignment can be changed to disastrous effects because of UREs.

The hard drives in RAID systems are growing in size. Systems can have multiple terabytes of drives connected together. These large capacity drives take days and hours to digitally transfer in a rebuild process. With the increased size and amount of time needed to transfer data, the danger of a second drive failing increases.

RAID systems are vulnerable to the same things as regular hard drives such as viruses, logical problems, and human errors. Because of their complexity, they are vulnerable to additional problems as well. When one drive fails in the array, the RAID runs in what is called a “critical state.” This critical state occurs when the hard drive has to retrieve compressed data from the parity blocks while running. This negatively impacts performance.

What Can I Do to Prevent Premature Failure of My RAID Server System?

That is an excellent question. Some of these tips apply to desktop computers and laptops as well. Heat is a major enemy of any electronic equipment. It can be especially damaging to computer equipment. Servers should be housed in cool, dry environments; often in a separate contained room. These computer rooms should be temperature-controlled to keep the equipment running optimally. Dust is another foe of computers. Keep the room clean and use air filtration to reduce airborne contaminants.

The next thing is to be aware of your RAID server’s age and defragmentation status. Hard drives are only guaranteed for 3-5 years. Beyond that time frame, hard drives will crash from software or hardware related breakdown. Make sure to stay up to date with your data storage capacity needs to not overwork your RAID server. This means buying new equipment and servicing your RAID system.

Use self-monitoring analysis reporting technology (SMART) to spot potential failures. This technology collects information on potential drive failures and error conditions. The sooner the technology recognizes an error, the quicker you can fix the potential problem.

Don’t force drives that have been marked as failing by the RAID management process or the application monitor. Forcing the drive back into action exposes the RAID system to a subsequent failure, and possible secondary failures.

The last thing, and the point that the Data Rescue Center always wants to get across, is always back up your hard drive and important files to a secondary disk image. Even RAID systems with their redundant information pattern can fail with catastrophic data loss. In the modern world, it is a necessity to have a backup protocol and automated schedule. If not, you can always see us at the Data Rescue Center.

About the Author

Jeremy S.

My name is Jeremy, and I write for Prosoft Engineering. I am passionate about hard drive disaster prevention and recovery. In my free time, I like to read classic literature and explore the Bay Area.