RAID Rebuild - Everything You Need To Know

RAID rebuild guide on how to rebuild raid array without losing data, cut RAID rebuild time, problems to avoid with RAID rebuild and more. A RAID rebuild guide for beginners!

One of the biggest hurdles you’ll face in your RAID rebuild quest (and to keep your storage array running flawlessly) is how to rebuild RAID array without losing data.

Here are a few RAID rebuilding tips from our certified experts  who handle RAID recovery services at TTR Data Recovery.

What is RAID Rebuild?

RAID rebuild is the process of reconstructing RAID array in the event that a hard disk drive dies. RAID rebuild puts every data into its proper order keeping a copy of the data in the event that a hard drive mechanical failure happens. Once RAID rebuild takes place, data is reformatted with parity data & RAID algorithm.

The intelligence of RAID algorithms and parity data comes into place when an unexpected hard drive failure has occurred. These two capacities of RAID makes it possible to reassemble the data that was funneled on a spare drive by the RAID array. 

These amazing capacities quickly activate in the event of an unexpected RAID failure to save the crucial data that RAID is tasked to protect. It maintains its accurate operation even with sophisticated data reassembling. 

RAID Basics

RAID arrays use groups of linked physical hard drives to create redundant architectures that can survive the drive failure of individual elements.

Although you see a single logical device when you access your RAID’s storage from a command prompt or GUI interface, they actually incorporate complex arrangements that leverage techniques like parity, striping, mirroring and other data storage methods to provide superior performance and dependable redundancy.

In the world of storage devices, RAID arrays hold a place of honor thanks to their versatility, reliability, and accessibility.

Although these configurations are extremely commonplace, however, they come with unique data recovery challenges.

4 RAID Rebuild Tips Every Beginner Should Learn

4 Raid Rebuild Tips Every Beginner Should Learn | Ttr Data Recovery

One of the advantages of RAID arrays is that you can recover their contents following many kinds of drive failures. If you lose some of the disks in your volume, then you might be able to use the information on the remaining devices to reconstruct the lost data. 

This process is known as RAID rebuilding.

The big problem with RAID rebuilding is that the operation doesn’t always go smoothly. 

For instance, some RAID rebuilds require you to wait for days until the process completes. Even worse, you might come up against a range of hurdles, such as unrecoverable read errors.

Every RAID administrator’s greatest nightmare is losing data during a rebuild. When you don’t follow the recommended procedures correctly, you could end up permanently eliminating vital information or corrupt the records that would normally let you access lost data.

Make a mistake, and you might lose any hope you had of completing a data recovery operation on your own.

Improve Your Odds With These Pointers!

Fortunately, you can do more than just cross your fingers in the hopes that your RAID rebuild will magically go according to plan. 

The following tips are great ways to lower the risk of mid-rebuild losses.

1. Learn How To Maintain your RAID Array

Learn How To Maintain Your Raid Array | Ttr Data Recovery

Certain factors significantly heighten the chances that you’ll lose data during a rebuild. For instance, if you’re trying to rebuild parity, then you face greater loss dangers by working with drives that include overwritten, or zeroed, parity records.

Other high-risk endeavors include reconstructing degraded drives that you’ve forced online even though their parity was overwritten or out-of-ordered devices whose parity and data were both overwritten.

Parity rebuilds aren’t the only tasks that you should approach carefully!

The process of RAID rebuilding from parity data can cause a raid drive to fail. Don’t try to rebuild a RAID array when a drive has gone missing, bears a dissimilar configuration or uses a disparate striping scheme.

Without accessible parity records, you’re running the risk of attempting to reconstruct data that it’s impossible to recover via normal means.

Suppose you try to correct parity by performing a rebuild on a drive, but the devices are out of order. Your good intentions might lead to other information getting erased via overwriting.

2. Understand Your RAID Level

RAID systems aren’t all equivalent. The different numeric levels that designate what kind of array you’re using are more than just naming schemes: They represent widely dissimilar data storage and redundancy record-keeping techniques.

It’s critical that you know the ins and outs of your array’s configuration before diving into a RAID recovery. Since a significant percentage of storage devices fail at some point in their service lifetimes, you should pick architectures that meet your needs and reduce your risks.

You also have to understand the nuances of what you’ve chosen so that you can rebuild properly.

3. Know Whether RAID Rebuilding Is Even an Option

Unlike professional hard drive recovery, RAID rebuilds can be extremely risky. While a secure data recovery service can use forensic techniques and specialized diagnostic tools to extract data from a drive, RAID rebuilds are primarily software-driven, self-guided processes.

If you attempt to do more than RAID levels can support, such as trying to rebuild an entire array from fewer surviving disks than the minimum number required to recover information, then you’re probably going to end up losing some information forever.

4. Make Backups Before and During RAID Rebuilds

RAID Rebuilding is designed to be a procedure of near-last resort, so you shouldn’t rely on it to solve all of your problems. If you’re smart, then you’ll create a regular system task that backs up your RAID array periodically so that you don’t lose too much if it fails.

You should also back up all of the disks in the RAID array before attempting a rebuild. Ensure that you label each backup clearly so that you can maintain the proper order if you need to reconstruct the volume from these reserves.

How Does RAID Rebuilds Impact End-Users?

How Does Raid Rebuilds Impact End Users | Ttr Data Recovery

RAID reconstruction is a process for data reconfiguring. This
process takes place when there is a need to replace an (HDD) Hard Disk Drive.

RAID rebuilds provide convenience for users by recreating data on arrays of RAID in case of an unexpected multiple disk failure.

This kind of solution is crucial for businesses that are sensitive to any disks failures. For enterprises that hold and process essential information, RAID rebuilds help them to recover from significant disks failures and resume their operations.

This technology enables businesses to save precious time by fixing their disk failures as fast as possible. Because with a problem like this that can halt the operations of a business, RAPID rebuild is a crucial solution to return a company’ service as soon as possible.

For businesses that hold sensitive information about their clients or customers, RAPID rebuild helps to protect this data by reconstructing this information after a disk failure scenario.

RAID reconstruction here means putting all these data on their
original and proper order. This technology would not be in any way useful for businesses if it can merely reconstruct. It responds to the business’ needs to recover the affected data on its original order. This capability has protected a lot of companies from significant financial losses and possible lawsuits.

With RAPID rebuilds capabilities, it can prevent problems from blowing up into proportions by operating fast and minimize the impacts of these failures. With this, it can return everything from normal operations.

How To Cut Back On RAID Rebuild Time?

How To Cut Back On Raid Rebuild Times? | Ttr Data Recovery

RAID rebuild time has been a problem for many users because of the rapid advancements in C&A technology, especially on the capacities of hard drives. The larger the hard drives’ size gets, the slower the RAID rebuild time can be.

With drives that are now on the 4, 6, 8 and even 10 Terabytes capacities, situations with RAID rebuild time has become more and more of a problem.

Fortunately, there are tried and tested solutions available even with the inevitable advances of technology that inflates the RAID rebuild time problem.

To solve the issue with RAID rebuild time this particular RAID problem is not to halt the progress of technology, but to utilize the solutions that lie underneath the existing technologies that we are using.

One solution to cope up with this problem is to give the recovery process a higher priority than the input/output (I/O) in the array of RAID.

Another solution is for the host to retrieve the maximum amount of data possible before a RAID recovery is initiated by allowing a failed drive to assist it.

Erasure coding is another solution to manage RAID rebuild time because through this erasure it can reduce the disk data to rebuild time and utilize fewer capacity overheads.

What's The Estimated Time for RAID Rebuild?

What's The Estimated Time For Raid Rebuild | Ttr Data Recovery

For a 300 GB hard drive, it takes 1 hour, 450 GB, 1.5 hours, 600 GB, 1.8 hours. For SAS type hard drives with 15,000 revolutions per second, the estimated RAID reconstruction time for a 300 GB hard drive is 1 hour, 450 GB, 1.5 hours, and for 600 GB, 1.8 hours.

For SAS type hard drives with only 10,000 revolutions per
second, the estimated RAID reconstruction time for a 450 GB hard drive is 2.5 hours, and 600 GB for 3.8 hours.

Lastly, for SATA type drives with 7,200 revolutions per
second, the estimated RAID reconstruction for a 2TB hard drive is 12.8 hours while a 3TB hard drive is 18.3 hours.

In other words, the estimated RAID rebuild time depends on the capacity of the drive, its types, and its (rpm) or revolutions per minute. All hard disk drives have a Fiber Channel types of hard drives and 15,000 revolutions per second.

2 Types Of Rebuild Errors That Can Lead To Data Loss

2 Types Of Rebuild Errors That Can Lead To Data Loss | Ttr Data Recovery

Errors with RAID reconstruction can be avoided, only if users are well aware of the common mistakes that they should avoid to prevent data loss. 

Here are the most common errors that users should know about RAID reconstruction

What Are The Misconfigurations Related To Rebuild Parity?

Misconfigurations must be avoided in rebuild parity to ensure a smooth operation in one’s system. Avoiding these things will ensure that one’s system can run in a desired manner.

Here are the misconfigurations that you need to avoid.

Misconfigurations Regarding Rebuild Raid

What is a Disordered RAID Arrays?

Disordered Arrays is the term used when the drives are in an improper order. Many might see this as a ‘minor issue’ in the overall RAID system. 

But with the complicated set up within this system, even minors issues can cause significant problems.

There is a need to be very careful when rebuilding RAID Array because minor misalignments can produce negative impacts on the whole system.

Users should always remember that parity rebuild on these misaligned drives may lead to the overwriting of essential and confidential data.

The overwritten data, users must know, are unretrievable.

Users must be aware if misalignments are occurring on their system, to avoid any operations that may work with these errors that can produce more significant problems.

Misalignment is a cause for concern, and it can turn into an unmanageable problem if it is allowed to “work in harmony” with another error.

What Are The New Configurations of RAID 5?

RAID 5 can use disk striping with parity. These two configurations are perfect combinations that ensure data protection from any failures.

  • It sets the standard by evenly balances read and writes, a method that is now widely used in most RAID methods today. 
  • It can continuously check if the data that it holds have been overwritten to prevent the possibility that these essential data can turn into unretrievable files.

RAID 5 has one of the most secure configurations of all RAID because of the vast extent of its parity data on all drives.

No wonder why it is the most trusted of all types of RAID because of its tight-knit approach on securing data.

What Are The 3 Causes of Data Loss Related To RAID Rebuild?

There are three common causes of data loss that is related to rebuild operations. Users must take not of these things as it can help them to prevent any data loss while they are in a rebuild RAID array operation.

Physical nature

Since the RAID system is composed of physical materials such as hard drives, it will always be prone to physical damages like wear and tear and drive head damages.

Accidental deletion of data

Accidentally deletion of data because of a human error would result in data loss but users can quickly recover it if the data is unwritten.

Failure of RAID controller

Since RAID controller manages all the hard drives in the RAID system, any failure in the controller would result in inaccessible hard drives, including the data within it. It can stem from power surges and rebooting the RAID can result in overwritten data that cannot be retrieved.

5 Pro Tips On How To Rebuild RAID Array Without Losing Data

5 Pro Tips On How To Do Raid Rebuild Without Data Loss | Ttr Data Recovery

Important: Never create new files on a disarrayed disk!

Creating new files can result in overwritten data and can
turn it into unretrievable files.

Users must always remember not to run critical applications or, more importantly, create any new files on the disarrayed disk because this will surely corrupt the drive.

A corrupted drive can directly affect all other areas, so it is necessary to avoid this failure at all cost.

Below are the 5 RAID rebuild tips  from our trusted data recovery experts.

1. Imaging The RAID Before A RAID Rebuilding

The main advantage of imaging the RAID before a rebuild RAID is it provides total protection for your data. Even without a guarantee from the rebuild, it will shield the data and imaging program can layout forensic or sector/block disk-image.

2. Separate Volumes

One of the first things that users need to do, before everything else, is to have a back-up of their data. This measure ensures that users can have recoverable data in case of any failure.

Also, it ensures that their data can still be retrieved even in the case of actively overwritten files. Remember that overwritten data can turn into an unretrievable file and will be inaccessible.

3. Test Backup With Multiple Restores

There is a need for users to image each drive separately. This action will ensure that a useful restore can jumpstart. Remember that it must be done, before and not after starting the RAID rebuilding process.

This action will not produce its desired result if users are not able to initiate this action before the process.

4. Run CHKDSK or FSCK tool only after taking the backup

Before running any repair utilities, users must make sure to initiate a secured and reliable back up and confirm it with proper steps in restoring. It will make the file system consistent through the option of overwriting file pointers.

Having a consistent file system ensures that everything can run smoothly, data are neatly organized and are in proper order.

5. Do not add, move, or delete files

These are specific actions that can complicate and slow the recovery process of data.

Any delays in the recovery process can surely have a direct impact on the operations of any business. This problem is an unwanted operations scenario, so users should avoid adding, deleting, or moving data if their RAID system is severely affected by failures, misalignments, and other related rebuild RAID problems.

Don’t Let RAID Rebuild Failures Catch You Off-Guard!

Data losses occur at the oddest of times, but this shouldn’t stop you from being as prepared as possible. Tracking the health and performance statuses of your RAID array drives on a regular basis makes it much easier to anticipate when things might go south.

If you’re consistently aware of how your hardware is doing, then you can replace faulty equipment promptly before it causes other problems that make rebuild RAID harder.

Finally, never hesitate to call a professional.

If you don’t know the exact cause of a failure, then it’s far better to solicit expert assistance than to try rebuilding RAID array yourself and make the situation even worse.

Learn more about maintaining your data security and privacy without potentially sacrificing your RAID’s integrity. Chat with TTR Data Recovery today.

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.