RAID RECOVERY – RAID DATA RECOVERY
Recovering Data from RAID Drives
A Redundant Array of Inexpensive Disks (RAID) offers high-performance data storage by maximizing input/output performance as well as drastically improving data transfer rate as compared to standard IDE devices. RAID disks combine the capacity of several hard disk drives but present a single volume interface to the user. In other words, RAID connects disks in parallel to make several hard disks appear as one drive. The increase in the number and capacity of hard disks in a RAID array increases the probability that one of the disks will fail. Fortunately, in most cases, lost data from RAID disks is retrievable.
Types and Objectives of RAID Storage
The primary objective of RAID storage is to be able to provide a large, fast data store which is also economical. A typical controller setup accesses several hard disks in parallel. Some RAID arrays have fault tolerance by the use of redundancy. Redundancy data is maintained through a method known as parity. Other forms of redundancy include Reed-Solomon and Hamming code. Typically, RAID configurations have seven basic levels:
• RAID 0 – This disk array setup offers the maximum performance although there is no redundancy or fault tolerance in this type of setup.
• RAID 1 – Also known as mirrored disks, data in this type of array is copied onto two disks, one of them acting as a redundancy.
• RAID 2 – This array is not common as it is built with error-correction data on separate disks. With the advent of error correction within the disk array itself, RAID 2 no longer finds much use.
RAID 5 RECOVERY – RAID 5 DATA RECOVERY
Data Recovery from a RAID 5 Array
The data recovery for a RAID disk array is very different from data recovery from a standard IDE hard disk. RAID 5 disks differ from other RAID configurations in that they allow for the distribution of blocks of data across disks (striping) and some data redundancy which allows data to be recovered even if one of the hard disks in the cluster fails. While this does not mean that RAID 5 is invulnerable to data loss, it does indicate a high probability of data recovery from the individual hard disks.
Understanding RAID 5 Architecture and Characteristics
RAID 5 is one of the most commonly applied configurations due to its suitability to high-volume transaction related storage. RAID 5 finds use in banking, computing for scientific research, medicine and other industries where a large number of transactions need execution. It offers the highest performance and stability on networks where repeated transaction data needs storage. RAID 5 disks are used in environments which require a high number of sequential ‘write’ operations.
One of the primary features of RAID 5 is the high read/write speed that is essential for stable systems. A distinguishing feature of the RAID 5 disk array is the presence of a parity bit – a single bit of data used to check errors in blocks of data stored on the disk. RAID 5 stripes data in bytes, which means that the data is spread out across disks more than other configurations. This feature, coupled with parity bits within each block of data gives a RAID 5 configuration unmatched fault tolerance. Parity in RAID 5 is often seen as a cyclic redundancy check.
RECOVER LOST FILES – WHAT SHOULD YOU DO?
Recover Lost Files
The retrieval of lost files is a crucial part of the data recovery process. Problems with lost files can range from not knowing the location of a certain file to recovering damaged files or file fragments from a disk.
There are several tools and data recovery solutions available to new users and advanced users. While some of these solutions involve some simple housekeeping on a user’s hard drive, others are able to convert file fragments in to completed files.
Lost Files: Causes
A typical desktop stores several hundred gigabytes data while servers store terabytes of data. This large data volume represents millions of files. A typical problem with large stores of data is the loss of files. Files may be lost because of fragmentation, accidental deletion, or disk corruption. Corrupted Master File Tables can cause the location of a file to be misplaced or misinterpreted by the operating system. In some cases, files could be lost because they are hidden or deleted from the hard disk.
What to Do When a File is Lost?
Before looking at professional data retrieval services or tools, it is important to ascertain if the lost file is still located on the machine’s hard disk. In the event that a lost file is an essential program file or a core system file, the operating system may cease to function. Some of the important steps a user needs to take before attempting data recovery are:
• Operating System Search – Determine the importance and criticality of the lost file and search for it through a standard operating system search (Windows + F key in Microsoft Windows). This search allows users to find lost and recovered scraps of files across all file formats supported by the operating system. New versions of standard search can help locate all indexed files including email and file fragments.
• Open source Search Tools – Misplaced files may be recovered by open source tools such as Locate32 and Power File Search that are able to scan for, report and locate hidden or lost files. These applications take far less time than standard search to locate a lost file due to their file indexing algorithm and are the next step in finding lost files.
Search and file finder tools help users ascertain the location of files on their disk. Some applications help the user restore the file to its original location on the hard disk, a feature which is particularly useful in situations where part of a file array or group of interdependent files is lost.
HOW TO RECOVERY DATA FROM A DEAD HARD DRIVE
Data Recovery from Dead Hard Disks
Dead hard disks pose a challenge to data recovery professionals because of the number of reasons a disk could fail. While software changes or a corrupted Master File Table may be repaired and rebuilt, hard drives usually fail because of defective hardware or damage.
This makes the recovery of data from these disks far less predictable. However, new recovery tools and methods may be used to retrieve data from dead hard drives.
Construction of a Hard Disk Drive
In order to understand how to recover data from a dead hard drive, an understanding of the basic parts and construction of a typical disk is essential.
A typical HDD consists of a base plate with a casing cover. This base plate has a power connector, a data connector (an IDE or SCSI connector which connects to the motherboard through a flat connector cable) and jumper pin slots which are used to specify the boot designation as a master or slave device.
The disk stores data on magnetic platters which are mounted on a spindle. These platters are read by special read/write heads which are moved above the platters by a slider arm attached to a central actuator device. The actuator is connected to a logic board by a cable. A failure to any of these parts may cause a drive to fail.
Reasons for Hard Disk Failure
There are several reasons for hard disk failure which render the data on them partially or completely irrecoverable. The causes of hard disk failure range from simple power connectivity problems to severe damage to the data storage surface of the disk. Some of these causes are:
LAPTOP DATA RECOVERY – Recovering Data From Laptop
Portable computers such as laptops and notebooks are prone to impact, liquid, temperature and magnetic damage – hazards of their portability.
While most laptops and notebooks are as secure as desktop computers, they are vulnerable to data corruption, deletion and virus attacks.
Today, recovering lost data from laptops may be accomplished through several do-it-yourself solutions or by data recovery professionals.
The Problem of Data Loss and Corruption
Data loss by accidental deletion of data or corruption of the Master File Table does not remove the original data from the hard disk, merely its reference in the file index. When a file is deleted, the memory location of the file still contains the file data but the operating system indicates that the memory location is free to be overwritten. Until the memory location is wiped or over written, the file contents remain there and may be retrieved.
There are several techniques used to retrieve data from laptop hard disks. While some may be performed by an experienced user, it is recommended that data recovery from physically damaged disks is performed by data retrieval services.
Simple Data recovery from Laptops
For laptops that have not suffered physical or irreparable damage, laptop disk adaptor kits are used to connect a laptop’s hard disk as a slave to another computer and recover data which may by copied from the laptop’s hard disk to a master disk.
RAID 0 RECOVERY – RAID 0 DATA RECOVERY
Data recovery from a RAID 0 disk array requires an understanding of RAID architecture. Fundamentally, a RAID array is an aggregation of hard disks which work as a single unit to the computer they are attached to.
The individual RAID disks do not appear as separate disks but as a single, cohesive logical disk volume. RAID 0, or striped array disks are a configuration of RAID disks which spread out data across multiple disks. Failures on a RAID 0 disks are not easily fixed because of the lack of fault tolerance mechanisms but it is possible to recover data from them.
Understanding the RAID Environment and Causes of Failure
RAID, or a Redundant Array of Inexpensive Disks are configured into several RAID levels of implementation. Numbered from RAID 0 to RAID 5, each raid type offers different levels of performance, security, fault tolerance and data protection.
RAID requires high-speed disks and is used for email servers, messaging servers, While RAID 0 provides the highest performance, it also provides the lowest data security and data lost from these disk arrays is significantly harder to retrieve than from a standard IDE volume. There are several causes of RAID 0 failure. Some of them include:
• Disk Damage – The failure of any single physical disk or multiple disks in a RAID 0 array may cause disk failure. This failure typically occurs if the disk is physically damaged.
• Extraction – RAID disks are placed in an order for data extraction, if the extraction order is changed or corrupted, the array may suffer data loss.
• Controller Failure – RAID arrays may fail if there is a single controller failure. Failure of the controller card may cause data loss.
• Configuration Settings Failure – The loss or corruption of RAID configuration settings or entries in the system registry may cause the array to fail.
• Incorrect or Missing Partitions – Incorrectly partitioning or inadvertent partitioning errors may cause a RAID volume to lose data.
Other factors such as virus attacks, inadvertent deletion and power fluctuations also cause data loss from a RAID 0 array.
HOW TO RECOVER DELETED FILES
Recovering Data: Safeguarding your Files
The consequences of an inadvertently deleted file can be anything from a minor inconvenience to a significant monetary loss. At home or at work, deleted files can represent hours or days of effort, wasted. Today, data recovery solutions can restore data files which have been deleted from the hard disk of your computer even if they have been deleted from the recycle bin or by a Shift+Delete keystroke in Windows which bypasses the recycle bin. So if you are wondering how to recover deleted files, there are several solutions that are available.
File Storage and Deletion
Here’s an example of using a data recovery program to recover deleted files:
Recovering data from a hard disk is possible because of the way information is stored on it. When a file is created or copied onto a hard disk, the operating system creates space to be allocated to the file, records the location of the file in a central directory and then places the file in the specified memory location.
When a file is moved, its location in the directory is changed. However, when a file is deleted, it does not remove it from the memory location, it merely removes the directory listing of the file.This means that the file still exists on the hard disk.
How To Recover Deleted Files using Data Recovery Programs
A deleted file remains in its memory location until it is overwritten or cleared from that location. Operating systems like Microsoft Windows use a Master File Table (MFT) to maintain a record of files. The MFT also has a mirror file for when the original MFT gets corrupted. In addition, each file, no matter of what type, has an individual file signature which identifies the file. These two features of files also enable programs such as Advanced Disk Recovery and other tools to retrieve files even after they have been deleted from the hard disk.
The recovery program answers the question of how to recover deleted files be scanning the disk for files and file fragments using these identifiers. Once identified, a program like Advanced Disk Recovery or R-Studio will indicate whether the file can be partially or completely recovered and what percentage of the file may be rebuilt. In many cases, these programs generate a large data dump of file and file fragments with their original paths. In Windows, these may be inspected in the detailed folder view to identify them. If a complete file is restored, it will appear in the folder specified in the program.
Online tools and programs have the capability to recover data from a variety of disk types, operating systems and file systems with basic encryption.
ADVANCED DISK RECOVERY SOFTWARE REVIEW
DATA RECOVERY AS GOOD AS NEW
There are few things that can match the terror you experience when you delete an important file or inadvertently reformat your hard drive. There was a time when you had to give it up as lost or pay a small fortune to recover the data. Now, all you need to do is keep a copy of Advanced Disk Recovery, a Systweak offering, within reach.
While you can spend a lot more for similar programs, for the small financial investment, you have a powerful program that is easy to use. The first thing you will notice is how easy and error-free it is to install. As soon as you get into the program, you will find all kinds of help available including that increasingly rare telephone support. Only a company that has confidence in its product would offer such a high level of support.
WHAT ADVANCED DISK RECOVERY DOES ?
The program lets you recover many problem files including:
• compressed;
• encrypted; and
• damaged.
You can recover files:
• from the recycle bin;
• those lost as a result of a power failure;
• those on disks with bad sectors; and
• those on a repartitioned or reformatted disk.
It supports IDE, SCSI, and Serial ATA drives as well as removable media and external hard drives. Finally, it works in the last three Microsoft operating systems including XP, Vista, and Windows 7.
This recovery program is efficient in its search for lost data and is capable of restoring this data to its original configuration. That means you got back just what you lost and not some jumbled files that may be more trouble than they’re worth.
DISK RECOVERY SOFTWARE REVIEWS
Majority of the computer users have experienced the frustrating situation of loosing a critical documents whether the system has frozen down or the system is knocked out by natural disaster or the data are deleted by key press mistake. Many people do not know that when a document is lost it is usually temporarily missing. It is have matter of having the right software the right tool or work of an expert to salvage the data. It is likely that the when user faces this type of uncertainty that his data are lost, he looks for assistance.
This article is a simple discussion on the data recovery basics and it would be great resource for a user to learn how data recovery works. When a file is disappears where it goes? Most people think that its mean that it has gone forever but the file still dose not removed from the hard drive. Keep in mind that files mean a page in a book. When the file is deleted the page is not destroyed from the book. The table of contents that points out the location of the page is erased. This part is tiny bit of information as compared to the whole file on the hard drive. After some time when you store new data on your computer this data will be stored on this specific place where the old file was located.
This pointer with other pointers of different files and folders on the computer is saved in a section near the beginning of the hard drive and is used by operating system to create the directory tree structure. When we delete the pointer file, he actual file becomes invisible to the operating system, even though it is still there until the file system reuses the space.
Finding the original table of content is the real challenge in recovering data which can tells us where the files actually exist. Qualified data recovery companies like Wonder share data recovery software developers have experienced engineers to develop software that can rebuilds file structure and save the lost files from being overwritten. So this is a matter of reaching those hidden places to recover the data which think is gone forever.
The science of data recovery is putting the file system back together so that the different type of data files can be accessed again. All operating systems have a file system which uses its unique method of indexing and keeping track of the files.
