Archive for the ‘Raid Data Recovery’ Category
Friday, November 6th, 2009
RAID stands for Redundant Array of Inexpensive Disks. This technology is usually a reliable storage option for computer users and have a better read / write speed versus single drive servers. If a drive failure, they also have a better fault tolerance and generally, superior data protection. But there are times when you could be faced with a raid data recovery situation.
Why are these systems as ideal for data protection?
They allow users to write data to multiple hard drives, so any failure of a disk in the array does not result in loss of data. As a result, many companies rely on a RAID system for critical data such as financial information and business system data such as e-mails, database application data, etc.
Although RAID-system RAID systems typically safer than other storage devices, these systems are still vulnerable to total system failure. How? Multiple drives may experience problems simultaneously. And the problem with this kind of data loss issues that businesses can come to a sudden stop, because data stored on the RAID array on business usually is crucial. And that is a big problem.
History
The RAID principle was developed by the UC Berkeley researchers, David A. Patterson, Garth Gibson and Randy H. Katz.
They worked on the production of prototypes for five levels of these types of storage systems. Their ideas have formed the basis and genesis of the current complex RAID storage systems.
What were the goals of this research?
Providing better performance, storage and recovery reliability, and scalability. The concept of redundancy employed in these systems is special. It helps restore the data to a disk in the system breaks. But do not worry – as a disk off-line, the RAID controller cards can continue to read and write data to other hard disks.
Levels
Level 0 includes what is called data striping. This basically stores the blocks of each file on multiple discs, but there is no redundancy. This is great for performance, but it is weak in terms of fault tolerance.
The collection of disks in a RAID Level 0, parallel data is accessed from different disks. Why? This type of array has the data organized in “stripes” across multiple hard drives.
Level 1 offers an ingenious idea – disk mirroring. With this concept, the data written to two duplicate disks simultaneously. As one of the breaks hard disks, the RAID system can switch to another hard drive without any loss of data or service.
RAID 1 improves the performance of reading, but the improved performance and the “fault tolerance” at the expense of available capacity on the hard drives.
Level 5. Of all levels is the most common level 5. It provides data striping at the byte level and also stripe error correction information to dramatically improve performance and help the recovery of lost data as a single drive failure.
raid 5 configuration
RAID Data Recovery
RAID Recovery Services can repair broken RAIDs. Let not your own IT team tries to repair the RAID system, by invoking the original configuration, or the documented administrative procedures.
Force a RAID controller even in a given configuration. This can cause further damage to your data. Data recovery specialists set the RAID configuration manually fixed. They do this by looking at all sectors of the data on all disks in a system, then for them to put back together.
The initial configuration may have deficiencies. Knowing that it ensures the reconstruction of distributed data blocks, drive order and data symmetry, until it is repaired. Specialists can even work on such systems as the original hard drive has failed by the virtual reconstruction of the RAID.
An advantage of RAID data recovery is the ability for the latest files and get back to the most recent backup. It is important to know, because often the RAID data storage with the highest value.
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Thursday, October 29th, 2009
Fault Description:
As Raid card hardware failure, resulting in four groups Raid5 in the three groups on the system can not be identified. Array of data is very important, even if the replacement Raid card, re-configure the raid information, and it does not guarantee data security. After further reflection, the customer decided to find a relatively safe ways to bring the data back out, and then decided to replace the hardware devices.
Solution:
The face in front of 42 from the array of pull down the size of the optical interface for the 146GB hard drive, technical engineers, if not a wealth of experience and deep knowledge of data recovery, one can not calm themselves, and second, convince customers. Escort age boys calmly took over the project.
The first step to determine the disk drive from the 1-42 group number, the first group, second group, the third group of faults Raid5 composed by 14 disk. Each raid of 14 tray is not a node 14 disk, but the number of nodes in the disk are, fortunately hardware engineers in the configuration when the raid made a detailed record of 42 provinces from the disk analysis which is a group of 14 disk raid5 time, raid5 disk group to confirm successful completion.
The second step, analyzing the data toward the bottom of this step is raid data recovery the most critical step in, if you analyze data from a group of raid5 combination of laws, the other two groups also turned out in a matter of course. With experience in the future, raid5 is the most common and relatively easy to analyze, which unlike the HP RAID ADG, Raid1 + e, Raid1 extended so as hard. Engineers quickly analyze the data combination of the law.
The third step, re-analysis of the data if the data is a key step toward the case, then the reorganization of data is the core technology. Fly-off data recovery with independent intellectual property rights of flight passenger data reorganization Raid software, any one can be re-Raid data. Some data recovery companies Whenever an algorithm is more complicated raid, with the market data recovery software can not do, they think can not be repaired. The fundamental is the non-professional skills, with the second-rate or free of foreign cracked version of the data recovery software to restore the high-end raid failure, can only be luck, there is no theoretical and technical support. Flying off raid recovery technology, which in theory can prove that the failure was incorrigible, and which can not be saved in.
Problems encountered in actual operation:
Days of unpredictable things can happen, people have good and bad fortune overnight. In the RAID data recovery process, the data not displayed in your eyes before you do not say OK, because there are more uncertainties in the head. Had thought that the first group fail raid re very smoothly, and did not expect that there is a 14 disk drive identification is not normal, then we lack in this block of disk data reorganization, did not expect that, when combined to the 70GB disk found in a large number of physical or bad Road, we can only terminate the program. When they find out there are two raid5 and two or more physical disk failure occurs, data recovery to this stage of people’s emotions is the most depressed and hard to endure. But the rule of thumb, we decided to have bad sectors on the hard disk to be a separate image, and then re-image files. If nothing works, we can only repair disk does not recognize a piece of. Finally overcome all the difficulties and successfully recovered all the data.
Summary:
In the high-end storage device fails, we must first think of the importance of data, in fact, this is a sense of thinking and a backup. If the data is very important, we recommend that do not make any exaggerated faulty equipment operation (refer to Rebuild, initialization, synchronization of data, re-equipped with raid, etc.), these operations are more fatal, is not reversible. To seek a professional data recovery company, to provide you with a reasonable recovery program, you can rest assured that your hard drive sent to the operating table. Those non-professional company, if asked to provide an array card or resume the server to do so, you should consider its technical reliability.
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Thursday, October 29th, 2009
RAID Disk Array
Although RAID with multiple hard drives, but the operating system as a stand-alone large-scale storage devices. The use of RAID technology in storage system benefits mainly in the following three ways: in the early stages of computer development, “high capacity” hard drive prices are quite high, to solve the problem of data storage security main method is to use the backup tape machines and other equipment, which Although the kinds of methods can guarantee the security of data, but access and backup jobs are quite tedious.
In 1987, Patterson, Gibson, and Katz the three University of California, Berkeley engineers delivered a speech entitled “A Case of Redundant Array of Inexpensive Disks (Redundant Array of Inexpensive Disks program),” paper, the basic idea is to more than just capacity of smaller, relatively inexpensive hard drive organic combination of its performance more than one big expensive hard drive.
The design idea was soon accepted, from RAID technology is widely used, data storage into faster, more secure, more affordable new era.
Disk Array for PC users, it is quite strange and mysterious. Impression of the disk array seem to stay in such a scenario: In the spacious hall, lined with the disk cabinet, several expressions gloomy, bald engineer early wandering, in which constantly out of a block from a heavy hard drive, and then Insert a block seems to be more heavy hard drive … … finally, with the large capacity hard drives continue to lower the price of personal computers continue to improve the performance, IDE-RAID disk performance improvements as the cheapest solution, started to enter the ordinary user’s computer system .
By combining multiple disks grouped together to provide the disk as a logical volume across functions;
By the data into multiple data blocks (Block) parallel write / read multiple disks to increase disk access speed;
By mirroring or parity operation to provide fault tolerance;
The main purpose of the initial development of RAID is to save costs, then the price of a few small-capacity hard drive to be less than the sum of large-capacity hard drive. Now look at RAID in the role of cost-saving is not obvious, but the RAID can fully play the advantages of multi-block drive to achieve far beyond any one single hard drive speed and throughput. In addition to performance improvements in addition, RAID can also provide a good fault tolerance, in any one case of hard drive problems can continue to work hard the impact will not be damaged.
RAID technology is divided into several different grades, respectively, to provide different speeds, safety and cost-effective. Based on the actual situation of selecting the appropriate RAID level to meet the users of storage system availability, performance and capacity requirements. Commonly used RAID levels are the following: NRAID, JBOD, RAID0, RAID1, RAID0 +1, RAID3, RAID5, etc.. Now regularly using RAID5 and RAID (0 +1).
RAID (Disk Array) is a hard disk drive controller to control the number of mutual connections, so that multiple hard drive read and write synchronization, reduce errors, increase efficiency and reliability technology. Disk array card is the realization of this technology hardware products, disk array card has a dedicated processor, also has a dedicated memory used to cache data. Server using the disk array card directly through the operation of the disk array card processing, so do not need a lot of CPU and system memory resources, not reduce the disk subsystem performance. Array card dedicated processing unit to carry out operations, its performance is much higher than that of conventional non-array of hard drives, and more secure and stable.
RAID technology, two main characteristics: first, speed second, it is safe, because these two advantages, RAID technology has been applied to the early high-level server SCSI interface hard disk system, with the development of computer technology in recent years, PC machine CPU has entered the era of the speed of GHz. IDE interface hard disk to be outdone, have launched a ATA66 and ATA100 hard drive. This makes RAID technology has been applied to middle and low personal PC, or even possible. RAID is usually caused by a hard disk in the RAID array tower controller or RAID card in the computer achieved. RAID is a Redundant Array of Inexpensive Disks English acronym, the Chinese referred to as Redundant Array of Inexpensive Disks. Simply put, RAID is a multi-block into a separate hard drive (physical disk) by combining in different ways to form a disk group (logical drives), which provides higher storage than a single hard disk performance and providing data backup technology. The different ways the composition of the disk array as RAID levels (RAID Levels). Data backup function is user data in the event of damage, the use of the backup information can allow corrupted data to be restored, thus protecting the user’s data security. The user appears to form a disk group is like a hard drive, users can partition it, format and so on. In short, the operation of disk arrays with a single hard drive exactly the same. The difference is that the disk array storage rate is much higher than a single hard disk, and can provide automatic data backup.
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Thursday, October 29th, 2009
Enterprise-class RAID disk arrays are often a powerful data security protection. However, due to operational errors and all kinds of unpredictable hardware failure, RAID failure inevitable. And that such failures occur, often brings huge economic losses, and many maintenance personnel often will not know what
Policy, or even part of the data recovery service providers are unable to cope with. In such a crucial period, maintenance personnel should be stopped as soon as possible of any non-professional operations, and seek to have the strength of professional data recovery service provider for help.
Data Recovery Services Insider: interns do you trust?
The causes of RAID is generally more complicated, especially Linux systems as well as professional database recovery, which is a lot of general repair software can not handle. Objectively speaking, the domestic data recovery market has just started, the vast majority of service providers from the original evolution from the hard disk maintenance. Such service providers may have a relatively rich experience in dealing with hardware failures, but for RAID repair software category will usually do nothing.
It is undeniable that the face of a large single-level RAID business, any data recovery service providers will not give up. Not only that, even its own technical strength can not meet the requirement, to suppress competition, as well as for the purpose of accumulating experience, so good “practice hand” would not of course the opportunity to give up easily. Customer data, however, priceless, what makes these companies lack the strength so bold it? Data recovery is like the same flutter Penalties: Puzhu is the great merit of a failure and without responsibility. Indeed, the particularity makes the data recovery service providers without having to take too much after the failure of responsibility, and even surgical procedures such as filling out the service in advance as a single, which also includes failures expected.
In this case, some service providers who naturally have no fear, bold hand, after practicing customer data is vulnerable to secondary damage, so that the final failure situation even worse. Even after the client was removed to find a regular data recovery service providers, because the data has passed through several operations and will make restoration much more difficult. For the time being not to comment on a small number of service providers in order to suppress their counterparts in the operation of vandalism after the failure of the terrorist phenomenon that is just hard for its technical strength, but is really worried people. As a major operation to find well-known doctors, you can rest assured that the valuable data to the low-cost “interns” do?
Service providers to see the strength of
How can we avoid falling into the trap of primary and secondary service providers, which is a lot of customers are thinking about the issue, but the mysterious data recovery industry, making them quickly in emergency situations can not make the right judgments.
China Server Net interviewed five well-known data recovery center, general manager or CTO (Technical Director), most of them that: a short time is impossible to understand the strength of service providers, because many technologies are confidential in nature, in the Prior to the signing of an agreement is not repaired, inquiring not see any details. More importantly, who would recklessly boasting! In this case, according to the size of data recovery service providers to filter is the easiest way, although this does not necessarily scientific, but basically can be done pretty close. Just think, if a data recovery service can only rent a small shop, then the amount involved in hundreds of thousands of business how to operate? If in the past have had considerable experience in this respect, then how could continue to adhere to the corporate image of such a small area of damage?
On the other hand, if a service provider in a local branch of the size of the parent company than other large-scale data recovery, which is proof of service of a simple way. In addition, the 800-free telephone number and search engine rankings can be used as a reference to determine service provider capability. Another point can not be ignored, that is, the technical strength of technical personnel in this area by talking with the technical personnel and technical staff to obtain an analysis of the fault. Of course, such practices are not tight, the Chinese server, Web-site visits suggest the best in the field, and reputation in the industry survey, but in emergency situations, when would be a good idea.
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Thursday, October 29th, 2009
The server has become the core of enterprise information, however, backed up by the cost of inputs and management measures to limit the restrictions, all kinds of people want to remember the RAID data to a disaster is always unexpected. Once the unfortunate experience of a server crashes, the whole enterprise will be very easy to fall into a passive situation, at a time when data recovery becomes the only resort. However, looking for data recovery service provider is not an easy task, because the data recovery operation itself is a certain risk. If you blindly valuable data delivered to the technical strength does not cross the boundary of the service providers, but will missing an opportunity, even cause irreparable damage.
One of the crises: after-sales service engineers to become a killer data
RAID in the face of the collapse, most IT departments are responsible people would first think of the server service provider. But the fact is that almost all hardware vendors are simply after-sales service equipment maintenance as a service base, which users to ensure data security is completely different from the starting point, so the end result often suffer greater losses for users, and even the formation of non – irreversible secondary damage.
RAID5 with some special case (such as RAID5 EE, RAID ADG), the entire disk array to allow two disks dropped. However, users will find that sometimes just dropped a plate can also cause RAID can not start, but this problem arises because of the diversity, and not merely in accordance with the server indicator to judge. For many server engineers are basically maintenance of equipment mainly for data storage are not familiar with. And if even forced implementation of the REBUILD operation is initialized, it is easy to make also want to restore the original data from total destruction. According to the nation’s largest chain of data recovery service introduced fly passengers, the National branch RAID recovery cases received per month no less than 100, of which around 10% because of the server operating engineers, non-professional difficulties which led to the restoration or recovery??.
Crisis 2: strength of no use of service providers “no morality” to practice hand –
It is undeniable that the face of a large single-level RAID business, any data recovery service providers will not give up. Not only that, even its own technical strength can not meet the requirement, to suppress competition, as well as for the purpose of accumulating experience, so good “practice hand” would not of course the opportunity to give up easily. Customer data, however, priceless, what makes these companies lack the strength so bold it? Data recovery is like the same flutter Penalties: Puzhu is the great merit of a failure and without responsibility. Indeed, the particularity makes the data recovery service providers without having to take too much after the failure of responsibility, and even surgical procedures such as filling out the service in advance as a single, which also includes failures expected.
In this case, some service providers who naturally have no fear, bold hand, after practicing customer data is vulnerable to secondary damage, so that the final failure situation even worse. Even after the client was removed to find a regular data recovery service providers, because the data has passed through several operations and will make restoration much more difficult.
In fact, the users want service providers to determine whether there is capacity to restore RAID is very simple, as long as the service providers from the point of qualification and background can be measured. At present the State Secrecy Bureau has conducted a single data recovery qualification awarded, while the service provider to obtain this qualification in the technical strength of the natural level of professional recognition, business users are fully capable of its confidence. Moreover, most restructuring came from the hard drive repair data recovery service provider, and there is no strong technology base, on the contrary, from anti-virus software vendors such as data recovery service provider in transition amounted to more capable. Order by Jiangmin Science and Technology funding for the creation of flight passenger data recovery center and Rising data recovery center, for example, the technical strength of these companies is more reassuring, but flying off the State Secrecy Bureau also obtained the qualification recognition.
In choosing data recovery service providers at the same time, experienced IT executives tend to attach great importance to service providers, qualifications, including technical strength and the confidentiality of information capabilities, while large companies even require service providers across the country to provide localized service and thoughtful.
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