RAID Failure [Ultimate Guide For Students And PC Users!]

RAID failures guide for students. Discussing the causes RAID drive failures like server died, and control failure! Ultimate RAID error guide for users!

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RAID Failure [Ultimate Guide For Students And PC Users!]

There are three common reasons for a RAID failures: 

    • One of the member disks failed;
    • More than one of the member disks failed
    • RAID Error control or operator control error and other failed RAID factors outside of the member disks!

It may seem uncanny to figure out how to avoid a RAID error.

Sure, you can opt to go with the RAID data recovery services of your choice if your circumstances does not allow you to troubleshoot a RAID error.

We deal with failed RAID day in and day out here at TTR Data Recovery, and our goal for this guide is to help users and students understand everything there to know about RAID drive failures, it’s symptoms and causes! For any questions related to data recovery, visit our FAQ page.

In this failures guide, we’re going to pick the basics up for anyone of you who wish to avoid dealing with RAID error issues in future troubleshooting!

Let’s begin.

What is RAID?

RAID, or Redundant Array of Inexpensive (or Independent) Disks, links two or more hard drives to form one large-capacity storage device. RAID comes in different RAID levels 0,1,5,6, and 10, they employ techniques like mirroring, striping and parity storage to create a much bigger and robust data storage.

What are the different types of RAID levels?

The types of levels are RAID 0, RAID 1, RAID 5, RAID 6 and RAID 10. Depending on the RAID level, an array uses Striping, Mirroring, and Parity storage techniques or a combination of these techniques. Storage Networking Industry Association (SNIA) standardized the RAID in DDF (or Disk Drive Format) standard.

RAID enables users to store the same data on multiple hard disks, offering improved performance and reliability. But this also comes with different problems with RAID!

RAID arrays also reduces the risk of data loss in the event that one or several of the disks fail or a RAID drive failures (fault-tolerance) as well as expand data storage capacity.

Raid Failure: RAID Levels and Their Weaknesses

Raid Failure Raid Levels And Their Weaknesses | Ttr Data Recovery

Now let’s discuss the main disadvantages of different levels and their weaknesses. The problems with RAID has to do with the RAID storage technique employed.


Understanding the problems with RAID, what happens on a failure and how the different levels react to a RAID error is crucial in choosing the right RAID for your needs!

Here’s a quick overview of the main problems with RAID, and the  of each RAID level:

What are the advantages and disadvantages of Each RAID Levels?

RAID 0Easy to Implement!Not fault-tolerant
RAID 1Fast read operationsHDD swapping not allowed when hot
RAID 5Data is secure even when HDDe fails.Complex technology
RAID 6High data accessibilityTakes longer to rebuilding RAID
RAID 10Robust and fast.Costly to build

RAID 0 Disadvantage - Not Best For Mission Critical Systems

Raid 0 Disadvantage Not Best For Mission Critical Systems | Ttr Data Recovery

RAID 0 is also known as disk mirroring. The RAID 0 has a configuration of at least two drives that duplicate data storage. You can optimize your storage capacity but there no overhead. 

It is recommended when you want to read/write stored data at a high speed.

Graphic designers and video editors use RAID 0 for their workstation.  However, despite its good performance in both read and write operations, it isn’t recommended for mission-critical systems because RAID 0 is fault-tolerant. 

When one RAID drive failure occur, all the data stored in the RAID 0 array is lost. 

RAID 1 DISADVANTAGE - No Allowance For Failed Drive Swap

Raid 1 Disadvantage No Allowance For Failed Drive Swap | Ttr Data Recovery

The RAID 1 offers users more diverse use over the RAID 0. In RAID 1, you are free to store data in two locations. The first is the live dataset while the second is a mirror drive. It also has great read/write speed compared to RAID 0 since it doesn’t rely on a single drive.

This means you can recover your data from the mirror drive in case your live dataset fails. 

However, it’s pitfall is found in its storage capacity. Since all the data in RAID 1 gets written twice, it demands high storage capacity to continue operation.

RAID 5 DISADVANTAGE - Failures Have a Direct Effect on Throughput

Raid 5 Disadvantage Failures Have A Direct Effect On Throughput | Ttr Data Recovery

The most secure RAID level is RAID 5. It can handle a single drive failure without data loss. This is possible because of parity data. Parity data is spread across all drives rather than written on a fixed drive like data does with RAID 0 and RAID 1.

It usually requires at least 3 drives but can also work with up to 16 drives in one data configuration.

It can read data faster but is slow when writing. To improve RAID 5 write performance, you can use extra cache memory on hardware controllers in achieving RAID 5 in software.

The downside is how complex the RAID 5 technology is. Its drive failures has a tendency to affect your output. It takes over a day or more to restore data when one of the disks in an array using 4TB disks fails. And when other disks go bad during recovery, your data is permanently deleted.

RAID 6 Disadvantages

Raid 6 Disadvantages | Ttr Data Recovery

Failure have a Direct Effect on Throughput

RAID 6 is similar to RAID 5 except its ability to write the parity data in two drives instead of one. It means RAID 6 requires at least 4 drives to work efficiently and can withstand 2 drives dying at the same time. Unlike RAID 5, it can also keep your data in the event of a second failure. 

It is more expensive, too. In RAID 6, you’re using 4 drives as opposed to the usual 2 or 3 in other RAID configurations.

Very Complex Technology Means Longer Repair Times

If you noticed, the more complex the technology is, the longer it takes to repair the drive damage. All RAID levels (except RAID 0) gives users protection against a single RAID drive failures. 

Since the RAID 6 is one of the more complex ones, rebuilding an array or raid rebuilds of one RAID drive failures can take quite some time in contrast to RAID 1 and 5.

So even though the RAID 6 is great at storing and securing your data. You might have to be patient when a drive failures occurs. But with the RAID 6, you rest assured your data won’t be lost permanently when things go wrong.

Additional Parity Slows It Down

Due to the additional parity data in RAID 6, writing data transactions is slower. Users report the write performance of RAID 6 is over 20% lower than the other RAID configurations.

RAID 10 Disadvantages

Raid 10 Disadvantages | Ttr Data Recovery

Half of the capacity goes to mirroring

RAID 10 is known as the combination of both RAID 0 and RAID 1. That is why it is also called a Hybrid RAID configuration. It gives users excellent security by mirroring data on secondary drives and uses striping across each set of drives for faster data transfer.

It can take just half an hour to transfer big terabytes of data and information. It takes just as long to rebuild it, too, when you encounter a fatal failures.

With that said, half of its storage capacity goes to mirroring so the drive cost is more expensive than both RAID 5 and RAID 6.

What are the different RAID storage Techniques?

What Are The Different Raid Storage Techniques | Ttr Data Recovery

To a computer or network, a group of hard drives in a RAID configuration appears to be a single device, known as a logical unit number, or LUN. LUNs employ various hardware or software techniques, such as:

    • Striping – Splits data flow into blocks written across the RAID. This technique is aimed at improving performance.
    • MirroringIdentical copies of data are read and written on pairs of drives simultaneously. This technique is for tolerance and to enhance performance.
    • Parity – Uses striping and parity computations and calculates the data in the first two drives and storing the resulting data on the third hard drives. This technique provides fault-tolerance as well as improves speed. In the unfortunate event of a RAID failures, data can be recreated from the remaining data and the Parity data.

What Are The Common RAID Failure Data Recovery Scenarios?

What Are The Common Raid Failure Data Recovery Scenarios | Ttr Data Recovery
  • You Experienced a Controller RAID Failure –  A controller is part of a RAID configuration.  RAID failure due to a controller malfunctioned or dies is the most common type of Data Loss. A power surge is the number cause of controller failure.
  • A Rebuild Didn’t Go as Planned – When you replace a RAID drive and rebuild the data that it formerly housed, errors could have disastrous effects. Interruptions in the process have the potential to corrupt existing data and make it impossible to access certain files or the entire RAID. If you experience a future RAID failure or data loss, it’s important to contact a RAID data recovery expert right away!
  • More Than One Disk Failed – You might lose multiple storage devices in a single cataclysmic event due to hard drive failures like power problems or hardware age. Such events can have various outcomes depending on what kind of RAID you were running.
  • The Partitions Mysteriously Went Missing – When used correctly, partitioning can help minimize speed loss on heavily used RAIDS or create functional redundancy arrangements on disks. When RAID features like striping fail, however, partitions may become so corrupted that the system doesn’t even recognize them or RAID is not found. Although they’re not truly missing in the physical sense, they’re as good as gone to their users.
  • The Server Died – The networked machine that hosts your RAID suddenly quit working or RAID is not found. Unfortunately, it’s not always as simple as just restarting the system. In some cases, a RAID failures or a failed server could have taken other things down with it, so you need a reliable, comprehensive RAID not found recovery strategy or a hard drive data recovery expert for that matter!

Identifying a Dependable Solution For Any RAID Failure

Identifying A Dependable Solution For Any Raid Failure | Ttr Data Recovery

What do these common RAID not found problems share? As unique as they are, all RAID failure require expert troubleshooting assistance.

Trying to repair common RAID not found issues by yourself only increases the likelihood that they might mutate into more dangerous faults.

For any RAID failure crisis, always play it safe by working with someone who knows what they’re doing. Discover more by getting in touch with a reliable data recovery services provider today!

Tommy Kh | Ttr Data Recovery

About the Author
Tommy Khamoushi, Data Recovery Expert

Tommy Khamoushi is an IACRB-certified Data Recovery Engineer and a Certified Forensic Computer Investigator. He has more than 20 years of experience in data recovery including providing technical support for the House of Representatives.

Tommy leads a team of data recovery engineers and experts at TTR Data Recovery to recover highly sensitive data for government agencies like the National Aeronautics and Space Administration (NASA) and enterprise businesses using advanced and proprietary techniques and processes.

Connect with Tommy on LinkedIn.