The Method For RAID Recovery You Wish You Know Before

"I'm in a bit of a tough spot. I have 3 drives that were configured in a RAID 5 array that I need to get some data off of them. I don't have the original server equipment available or controller card that was attached to them. The array is complete, none of the disks are in a failed state. They were just removed from the previous server.

Is there any way possible to recover the data from them? Possible using a usb connection of some sort?"

Maybe you’re familiar with this kind of case, maybe you’re troubled by such problem right now; either way, it indicates RAID recovery is a topic that can’t be ignored.

Obviously, RAID recovery refers to the process of data recovery from a RAID array which encounters problem for whatever reasons (maybe it happens due to uses’ improper/wrong actions, a controller problem, the virus attack or something else).

In fact, if you search "RAID recovery", "RAID data recovery" or "RAID file recovery" in Google, you’ll get lots of results within a few seconds.

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According to this, you can easily find users’ urgent demands for RAID data recovery/RAID file recovery. At this time, you’ll think about other related questions: what is RAID exactly, why people choose to set up a disk array, how data are lost from RAID and could it be easy to recover data from RAID arrays. Now, let’s talk about them one by one.

What Is RAID Exactly

A RAID consists of several cheap disks, so it is a disk group with huge capacity. The principle is: RAID uses individual disk to provide data, producing additive effect so as to enhance comprehensive effectiveness of the entire disk system.

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On RAID, same data will be saved respectively to different places of different disks in the array. In this way, the input and output operations can overlap in a balanced manner to improve disk performance. By taking advantage of parity check concept, RAID is able to read data even when a disk in the array is failed. What’s more, data on the failed disk will be transferred to new hard disk after reconstruction and calculation.

As a result , the MTBF (Mean Time Between Failures) is increased due to multiple disks; at the same time, redundant data storage increases fault tolerance as well.

FYI, the full name of RAID is originally Redundant Array of Inexpensive Disks, now Redundant Array of Independent Disks.

Common RAID Types

According to different classification methods, RAID array can be divided into different types. The 2 most important classification criteria are creating way and function. By which, RAID is divided into following types: software RAID and hardware RAID, RAID 0, RAID 1, RAID 2, RAID 3, and so on. Different RAID levels have different pros and cons.

  • RAID 0: based on Data Stripping, RAID 0 is the earliest RAID mode. It is also the simplest form of disk array which needs at least 2 disks. Though RAID 0 has a low cost, it’s able to improve the overall disk performance and throughput.

  • Deficiency: it does not provide redundancy or ability to fix bugs.

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  • RAID 1: it is also known as disk mirroring, which provides data redundancy. The principle is to mirror data from one disk to the other one. That is to say, when data is writing to one disk, the corresponding image file will be generated and saved on the other disk. This could ensure maximum system reliability and repair ability without affecting performance.

  • Deficiency: only half of the disk capacity is effective, which increases cost indirectly.

  • RAID 0+1 (also known as RAID 10): it’s the combination of RAID 0 and RAID 1. RAID 10 can be simply understood as the mirroring of RAID 0 arrays. It has the following features.

  • Offer fast read/write capability.
    Offer full redundancy capability.
    Data are distributed across multiple disks.
    Each disk has its own physical mirroring disk.
    Allow disk failure without affecting data availability.

  • RAID 5: its parity code exists on all disks in the array, so the reliability is increased. The principle is cutting data parity on each disk into pieces and saving them to all disks in the array. This eases the bottleneck problem arising from parity data storage at the price of sacrificing speed.

  • Deficiency: data transmission parallelism and the design of controller are hard to handle.

Brief comparison of software RAID and hardware RAID:

Software RAID is created by software totally (there is no need for the hardware to be actually configured as RAID drive) while hardware RAID is really a hardware based mechanism. But, they have no difference in function.

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Why People Set up RAID

3 main purposes of creating RAID array are: to gain data redundancy, to provide fault tolerance via data parity and to improve transmission rate (so as to achieve better disk performance).

Besides, when users get their hands on deploying an enterprise class server, RAID is essential for them. Why? It is simple to explain – redundancy is very important for a server system since the drive may be failed and the server may be crashed, resulting from many unexpected issues.

In a word, RAID is necessary in some cases to help users increase disk performance in the way they want. And the creating process of disk arrays is not so complex that most of users can actually finish by referring to online tutorial. What really matters is that RAID data loss takes now and then due to different reasons. At this time, users’ will naturally give top priority to RAID recovery. But how? Our suggestion is using omnipotent RAID data recovery software.

How Data Get Lost from RAID

As we mentioned before, RAID offers high performance to computer users, especially those who’re handing with servers. But in the meantime, it is also likely to bring troubles to users. There’s a typical point of view – when system crash, virus attack, power failure/surge or other unknown reasons lead to data loss on RAID disk, things will be more complicated than data loss on a single disk.

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That is because data recovery from RAID drives seems to be more difficult for ordinary users. They don’t know at all what to do or what they shouldn’t do at that moment. Some of them are even like ants on a hot pan and would do whatever is said possible to rescue their RAID.

But what we want to say here is: this is totally wrong! Any operations performed after data were lost from RAID could bring secondary damage to the lost data and it may result in a devastating result – permanent loss of data. Even the best software for RAID or the most professional data recovery experts can do nothing once lost data are overwritten.

6 Causes for RAID Data Loss & 3 Suggestions

1.RAID array card fails.
2.Physical disk failures, such as bad sector, disk error and long disk responding time.
3.Sudden power outage on array cabinet or server without UPS protection.
4.Booting system with wrong disk order or unreasonable change of array configuration data.
5.Improper reconfiguration of RAID disk array information.
6.Unstable power supply, leading to the loss of RAID information.

img4 Please take following measures immediately when failure is detected on RAID disk array:

1.Save all pending files & documents and power off the system properly.
2.Report the situation to disk array manufacturers or resort to professional disk array data recovery company/RAID data recovery software.
3.Please don’t attempt to do data recovery operations, such as rebuilding and synchronization.

All in all, please hire professionals to help you get rid of RAID data loss trouble. Do not try anything in person unless you have confidence in making data recovery from RAID drives done all by yourself.

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How to Recover Data from RAID

Earlier, when users meet RAID data loss unfortunately, they have no choice but to either look for professional RAID data recovery companies and pay much money for the recovery, or buy expensive RAID data recovery software to do the recovery.

Now, the good news is users have a better choice: complete data recovery from RAID drives with the best free software for RAID – MiniTool Power Data Recovery – which perfectly supports common RAID types.

Though in RAID 5, the disk array can work well even when over two or more disks are damaged, RAID data recovery from damaged or corrupt RAID arrays is still important. That is because the data saved on RAID are often too significant to lose.

Now, we’re going to focus on RAID 5 recovery on different platforms.

RAID Recovery for Windows

For the purpose of recovering a RAID-5 volume that is damaged, users should choose "Damaged Partition Recovery" function from main interface of MiniTool Power Data Recovery.

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After that, above interface will appear and ask users to select the volume they’d like to recover. Now, we need to choose Volume K and press "Full Scan" in order to search for the lost files from RAID 5 volume.

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Then, found files will be displayed one by one in above interface, in which users are supposed to select all they need to recover. If there’re too many files waiting for users to choose from, users could make use of "Find" or "Filter" function to narrow search scope.

Besides, if the data need to be recovered are pictures, photos or txt files, users can select a file and click on "Preview" button from the right panel to see the real content so as to determine whether it is the one they need or not.

When all needed files are selected, users should recover them by pressing "Save" button and setting a safe storage location.

To recover lost data in Windows under other circumstances, users should choose another function from the 5 different functions shown on the main interface. For example, if users plan to restore completely deleted files in Windows 7, they should just choose "Undelete Recovery".

img5 This post will show you all you need.

  • If the total size of files waiting to be recovered is more than 1GB, users should buy a license to upgrade their software from free edition to an advanced edition.

  • If the RAID 5 array with lost data is running on a Windows Server system, users need to buy an advanced license except for Personal License in order to recover lost files successfully.

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To know more differences between different license types, users could just click here.

RAID Recovery for Mac

If users are running the RAID array on Mac, they need to use MiniTool Mac Data Recovery instead. They can also download the software from download center free of charge, but the difference is – Free Edition of Mac Data Recovery only allow users to scan lost files for free. Therefore, if users find what they need after scan, they should buy a license to do the RAID recovery.

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There’s no difference in using this data recovery software for Mac. Users should also choose a suitable function from main interface, select the target drive to scan and check all they need to recover.

In short, what users should do after they found data loss on RAID are stopping using the RAID, closing computer, downloading specific MiniTool data recovery software and performing RAID recovery step by step under guidance.

Common problems related to partition recovery and our solutions: