3:18 PM Mintrukpare
All About RAID


RAID
is the short form of Redundant Array of Inexpensive Disks, where Inexpensive is often replaced with Independent. A few years back when the disks had less storage capacity with expensive prices, a couple of disks were mounted to create a larger virtual disk, and it was much more logical and easily administered.


All the disks are all placed in a confined area and if one disk
crashes then a very useful amount of data can be lost. In order to avoid this is a technique called ‘Mirroring’ is taken into consideration. The data from all the disks is copied to another bulk of disks, so that if there is any corrupted disk then it would be replaced with its mirror disk. This is done for the complete integrity of your mission-critical data.


RAID Types
Although there are many types of RAID arrays, but the ones explained below are the important of all.


Concatenation:


This type of RAID array is called ’Simple’ RAIDs.
It is a group of disks that are connected together tightly. Data is distributed in a linear pattern on the disk. Data is written a sequential order i-e, first disk is filled and then the text gets written on to the next disk and so on. All this is done by the volume manager, who is the in charge of the RAID. If we have less data as compared to the total size of all the disks combined then it is useless for us.



RAID-0:
It is also known as ‘striping’. Striping is much similar to concatenation, but data processing of RAID-0 is much better than its predecessor. Whenever we write some data it gets stored across all the disks. So when there is a request for data retrieval or placement it is executed much faster. Stripe width and columns are the things which make this type important. -Stripe Width: It specifies the amount of data to be written on one particular disk.-Column: It refers to each disk. A major flaw of RAID-0 is that if a single disk crashes than the whole system can collapse, since the data is stripped across all the disks.


RAID-1:
This type of RAID is called ‘Mirroring’. Though it’s not actually a RAID but sure is an important component of RAID. The logic behind this technique is to create a mirror image of your RAID. So that if a particular disk crashes, then the mirror will play its part. Mirroring is an excellent way of protecting the business critical data, but it comes for a good amount of money.


RAID-0+1:
This type combines Stripping and Mirroring together. We place a bunch of disks, which acts like mirrors to save the stripped data. One important thing to know is that the mirror has to be the same type of RAID as the original RAID. If we want to make a mirror copy of the simple RAID, then our mirror will be simple RAID and vice versa.


RAID-5:
RAID-5 is the best solution for increasing disk space and disk redundancy by leaps and bounds. It is similar to RAID-1 as it contains columns and stripe-widths. The difference appears when we write data. The data is written to the multiple disks at the same time, parity is also written along the data.

So even if a single disk fails then no need to worry since the data is saved on the remaining disks. Though we get quite pleased with the results but all goes in vain when we think about I/O bandwidth.
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11:29 AM Mintrukpare
How Data Recovery is Performed on Failed RAID 5 Arrays







RAID 5 arrays are used for many applications because they are for the most part cost-effective and provide a level of fault tolerance not provided by some other levels of RAID. As with any RAID level, RAID 5 can experience many different types of problems. This article will provide a brief discussion of some of the problems causing RAID 5 failure and how data recovery can work to solve these problems.

Problems That Can Cause RAID 5 Failure

Bad Sectors

A RAID 5 can fail due to bad sectors on any of the disks in the array. This can force the array to go offline.

Corrupt Data

A RAID 5 can suffer from corrupt data due to many reasons including viruses, user error, overwriting files, and scratches on the surface of the disk platters.

Degraded RAID 5
A RAID 5 becomes degraded when there is a loss of one of the member disks. This causes a huge decrease in performance and also removes the fault tolerance of the RAID 5. Operating a degraded RAID 5 is dangerous because the loss of a second disk will cause the entire array to be lost.

Deleted Files

Many times a user will accidentally delete important data in a RAID 5 array. Other times, it is done intentionally by disgruntled employees. In most situations, deleted files can be recovered.

Missing Partitions

In many cases, the partition table can become corrupt or missing causing an entire partition to disappear or become unusable. This makes data recovery necessary. Attempting recovery with software will increase the risk of permanent data loss.

RAID 5 Controller Failure

A Hardware RAID 5 array uses a controller which contains all of the logic and handles the operations of the array. For many reasons, the array can experience a controller failure. This can cause the array to not boot. It could also cause the logical volume to disappear.

RAID 5 Disk Failure/RAID 5 Drive Failure

A RAID 5 is a set of three or more disk drives. Any of these drives can experience failure. A RAID 5 is configured with the ability to withstand the failure of only one disk at a time. In most cases, the RAID can be recovered in a data recovery lab using parity data written to the disks by the array. Even if more than one disk has failed, data recovery is still possible in a recovery lab.

RAID 5 Firmware Failure

Firmware problems can occur in the RAID controller or the member disk drives.

RAID 5 Rebuild Failure

For various reasons, a RAID 5 array can experience a rebuild failure. This may keep member disks offline and render the array unusable.

Server Crash

Many times, the host server experiences problems and can crash. This of course makes the array unaccessible. A data recovery lab can recover the data from the member disks.

How to Ensure RAID 5 Data Recovery is Successful

If you have experienced a RAID 5 failure, it is important that you do not take matters into your own hands. This can cause the parity data to be overwritten. Parity data, which is written to the member disks, is in many cases vital to ensure a successful recovery. The very first thing you should do is power off the RAID server immediately to ensure that no additional writes are performed. Any events describing what may have happened to cause the problem should be noted. If the member disk drives are removed from the server, they should be labeled in the correct order they were removed. The disk order is very important if time is of the essence. This is also important if you have a large number of member disks.

To ensure a successful data recovery, it is important that the failed RAID 5 remain intact. More information can be found by visiting RAID 5 recovery.
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12:25 PM Mintrukpare
Easy Guide to RAID Recovery




What is RAID RECOVERY?


RAID stands for Redundant Array of Inexpensive Disks. It is a method of combining several hard drives into one unit. This method offers fault tolerance (the ability of a system to continue to perform functions even when one or more hard disk drives have failed) and higher protection against data loss than a single hard drive.


Why do I need RAID RECOVERY?


RAID provides real-time data recovery when a hard drive fails, increasing system uptime and network availability while protecting against loss of data. Another advantage of the system is that multiple disks working together increase overall system performance. Any individual or company could benefit from having a RAID RECOVERY system in place.


Different Levels


There are several different levels of RAID available. Each level offers various advantages in terms of data availability, cost and performance. Your best bet is to assess your needs in order to determine which level works best for you. The most popular RAID systems are the following:


RAID 0 - Data striping (no data protection).

The benefit of this system is that it offers the highest performance.


RAID 1- Disk Mirroring

(provides data protection by duplicating all data from a primary drive on a secondary drive). The benefit of this system is it offers the highest data protection.


RAID 0/1- This combines both Raids 0 and 1.

The benefit here is highest performance + highest data protection.


RAID 5 - Data striping with distributed parity

(a form of data protection that recreates the data of failed drive in a disk array). This system offers the best cost performance for multidrive environments.


Having a RAID system

installed can provide peace of mind. With RAID installed you can rest assured that even in the event of a system failure your important data will be safe.

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3:18 PM Mintrukpare
Raid Data Recovery Explained





Raid data recovery

is somehow different from all other types of data recovery. Most experts advise not to try to recover the data yourself before sending in the hard drives to a data recovery company. This is because most companies found that most of the times simple users try to recover the files all by themselves, they fail and not only. Their actions will make the recovery process even harder and if the lost information is important, someone will be in big trouble. If it's about raid data recovery better handle it quick to the professionals without touching anything.


You don't have to take chances with the recovery,

it's advised to research for a data recovery company that can handle the recovery process for you. Sometimes, it can be expensive for a raid data recovery but usually the price you will have to pay for the recovery is way lower then the price you will have to pay in time and resources to have all your data recreated.
There are procedures that data recovery companies always follow when they have a recovery on the line. These procedures are followed exactly and even expand when it comes to raid data recovery. As a first step in any raid data recovery, experts have to make sure that all drives are working. For Raid 0 as an example, it is a must for all the drives to be 100% functional. When they are not functional, the drives will be taken in the clean room and will be repaired.


When all the drives will function normally,

clones of all the drives will be made. During this process, your drive will be placed in a write protect mode to make sure the data will not be altered in any way. The normal recovery process will be performed on the cloned drives, again, for increased safety.


When researching for a data recovery

company you will notice some of them will offer a service full guarantee, if they don't get your data back, you don't pay. A phone consultation is something that could help you also. They will also offer you absolute 100% confidentiality on your data.
Even if raid data recovery sometimes can become expensive, most companies will not charge you for an evaluation of a complex raid system. If you need the help of the experts, get it, it's the best way. After getting all your data back, make sure to always backup your information from now on.

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3:18 PM Mintrukpare
Introduction to RAID 5 Arrays




Definition of a RAID 5 Array

A RAID 5 array uses at least three disks and stripes information at the byte level across the member disks. Parity data is also written across each member disk to allow the RAID data to be recovered in the event of a disk failure.

Different Ways a RAID 5 Array Can Be Set Up

A RAID 5 array can be set up as a software RAID using special software or as a hardware RAID using a RAID controller.

A software RAID is generally
either set up using standalone software or using RAID software which is built into an operating system such as Windows 2003 Server. A software RAID uses the CPU and memory of the computer on which it is installed. This can slow down other applications on that computer. This also makes the software RAID vulnerable to failure due to problems with the host computer. A hardware RAID uses a RAID controller which handles array duties thus there is no strain on the host computer's CPU and memory.

Applications Best Suited for RAID 5

Since RAID 5 offers better read performance than write performance, it is best suited for read-oriented applications such as web, intranet, and email servers. It could also be suited for databases as long as there is more reading than writing. With RAID 5, writes are slowed down because the array must write parity data to the disks.

Advantages and Disadvantages of RAID 5 Arrays

There are several advantages from a RAID 5 array. Since a RAID 5 writes parity data to each of the member disks, a RAID 5 can sustain the failure of one disk. The parity data allows the RAID to be recovered. Another advantage of RAID 5 is that it is fairly cost-effective considering the amount of fault tolerance it provides. Finally, RAID 5 offers a good rate of reads to the member disks. Some disadvantages of RAID 5 are that it offers slower writes as it must write parity data in addition to regular data. It can also be expensive to implement as it requires special hardware.
Conclusion

Overall, RAID 5 offers excellent fault tolerance without wasting drive space.
It also offers a high read performance making it suitable for a wide variety of applications. More information about RAID 5 arrays can be found at RAID 5 Data Recovery.
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