A RAID-5 volume is a fault-tolerant volume with data and parity striped intermittently across three or more physical disks. RAID 5 stores data on each drive at the same time in the form of blocks called stripes. RAID 5 efficiency goes up as the number of disks increases. If a portion of a physical disk fails, you can recreate the data that was on the failed portion from the remaining data and parity. RAID-5 volumes are a good solution for data redundancy in a computer environment in which most activity consists of reading data.

With no dedicated parity drive the write performance is better, with overlapped data and parity update writes. Read operations can be interleaved as all drives contain data stripes. RAID 1 performs faster but RAID 5 provides better storage efficiency. Parity update can be more efficiently handled by RAID 5, by checking for data bit changes and only changing the corresponding parity bits. For small data writes improvements here are lost as most disk drives update sectors entirely for any write operation. For larger writes only the sectors where bit changes need to be made are rewritten and improvements made. Maintaining parity information reduces write performance ? in some cases as low as one third the speed of RAID 1. For this reason RAID 5 is not normally used in performance critical processes.
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The fastest fault tolerant array configuration but the least storage efficient array, it’s probably the most commonly used system today. As other array configurations require three or more drives, it is the only choice in a two-drive system. The two drives in the ‘mirrored pair’ appear to the operating system as one; they always mirror each other. Should a drive fail the data is available from the other. If you cannot access data from either of the mirrored arrays, you must be having a bad day because this is the most reliable storage array.

As the data is always the same on the two drives, read performance is almost doubled, as consecutive reads can occur on each drive at the same time. Write performance is not improved.

If you have any problem with RAID 1, find out which array is problematic and try to access the data from the other array. If you cannot access data from either of the arrays then at that stage you need professional help for data recovery. Further tries to recover data yourself may lead to more damage to problematic hard drives in the array. This will increase data recovery cost and in some cases, it even makes data recovery impossible. If you had any questions, feel fry to call us for further assistance.

This is the simplest RAID Level, the fastest and most storage efficient configuration of a group of disks, but it has no fault tolerance. Files are broken into stripes of a size dictated by the user-defined stripe size of the array, and stripes are sent to each disk in the array if one drive fails the whole array fails. As there is no parity, it offers the best storage efficiency. The striping allows read/write operations to occur simultaneously on each disk for speed. This is most popular RAID Level for performance seekers.

If you are having problem with RAID O, the chances are that one of the drives used in the Array have physical problem. At this point, we suggest to shut the server down and get the professional help. Trying to recover data that this point may do more harm to the problematic drive and may lesson the chances of data recovery.

Why do I Need Backup Software?

Why not just copy the files you care about onto a blank CD and store it somewhere safe? There???s a good chance the irritation factor of doing it repeatedly will result in the user neglecting to do it as often as they should. Good backup software essentially makes the whole process a bit less bothersome than it would be otherwise. How?

List of features you can expect to find in any decent backup software

- Data compression. Any backup software worth its salt will be able to compress your data so it doesn???t take up too much space on the final storage medium. Savings can be significant. Some packages even allow you to alter the compression values. In general, higher compression rates mean the backups take more time to perform so, if compression settings can be altered, you can decide for yourself what your preferred time\compression trade-off is.

- Encryption. Backup software should allow you to encrypt your data. Some of it could be personal or commercially sensitive. Whether you???re backing up to an external storage medium, or elsewhere on the network, when you create copies of your data you multiply the chances of it falling into the wrong hands. Encryption is essential to making it secure.
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Disk Doctors Linux Data Recovery software is a user-friendly tool that allows you to recover data from the Linux Ext2 & Ext3 File System created from on any Linux Distribution. All of the most prevalent Linux distributions are supported. These include Redhat Linux, Suse Linux, Mandriva Linux, Ubuntu Linux, Caldera Linux, Slackware Linux, Gentoo Linux, Kubuntu Linux and many more.

How is data lost on a computer using a Linux Operating system?

Linux is a wonderful speedy operating system. It is unsurpassed for streamlined functions such as accounting or compression of large amounts of data. But the Linux based file system?? is somewhat prone to data loss, it seems as if the speed of Linux results in errors. Using Linux, you may face data loss due to any of the following hard drive segmenting and file storage problems:
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Among the problems with recovering files on Linux is the fact that it is often a multi-user system, with processes writing to the disk at any time with any amount of data. As it is important in data loss situations to not write anything to the affected drive, this can complicate matters and decrease the likelihood of a successful recovery.

Another problem is that Linux (UNIX in general) is unlike other operating systems when it comes to un-deleting files. Under Linux, the procedure typically involves (in short) un-mounting the file system, finding the data blocks on the raw device, and manually copying the blocks to another partition. This requires a fair degree of knowledge of how the file system works. It is therefore imperative with Linux, as it is with other operating systems, to keep backups. Commercial backup software is available from Storix, PowerQuest and Arkeia, and many other free options are also available.

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Data recovery from RAID systems and Hard Disks: Recovery of data from a RAID configuration can be a lot trickier than recovery from stand alone hard disks. RAID 0 and RAID 1 used together (RAID 0 + 1) and RAID 5 offer the best levels of protection. Of course with the simplest form of fault tolerance i.e. RAID 1 the second hard disk mirrors what’s on the first one and should one of the hard disks go faulty the other one will seamlessly take over. In RAID 0 of course there is double the chance of losing your data. You need only one of the hard disks to go faulty and you won’t be able to boot into your operating system.

However, there may be occasions when you need a specialist data recovery service. Instances are when the power to your hard disk has failed and you are unable to get it to spin. Unless you have an exact copy of that hard disk and are willing to roll your sleeves up and swap power units/motors on the drives and willing to take the chance of not mucking it up you would probably want to get a specialist in. Specialists will also often be able to recover data from
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Data is stored on media like hard disks, RAID configurations of hard disks, magnetic disks, tapes, CDs, DVDs, floppy disks and other storage media. Data gets damaged or missing in a variety of ways from virus attacks to improper storage of the media to accidents like floods. It could also have simply just been erased. Very often a large percentage of this data can be recovered using a variety of techniques.

Recovering or salvaging the data from such media can sometimes be performed using simple hardware or software but may occasionally require the assistance of data recovery specialists.

Some examples of data recovery:

- With optical drives there are options to repair the small nicks and scratches on the underside of your CD/DVD. Some consumer level repair products are available from your local PC shop. They often involve a two stage process of filling the nicks and then sealing the surface. Done correctly this will sometimes allow reading of data that was previously inaccessible.

- With hard disks the fault could be either mechanical/physical or logical. If the motor or PCB (Printer Circuit Board) of the hard disk is damaged but the platters themselves (where the data is stored) are intact then the motor/PCB could be replaced with another one. If the mechanics are undamaged but the data has been deleted/written over or the “index” of the files has been damaged a Hex Editor will facilitate the viewing of the drive in absolute sector mode i.e. one sector of 512 bytes at a time. The first sector of your hard drive is used as a partition block providing information on disk size/partitions/file system etc. And, from there, markers to the previous “location” of your data can be found.
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Last year, 22,800 people called Fields Data Recovery for help and advice when they suffered critical data loss. From IBM to the US Department of Defense, we were consistently selected by the worlds leading IT professionals as the number one choice for data recovery.

At Fields, we understand how important your data is. Whether you???re an international giant like Warner Brothers or a student who???s lost his thesis, we???re committed to recovering your data as quickly and cost effectively as possible. Last year, we regularly recovered data from media that other data recovery companies said was impossible.

With over 15 years experience, we recover data from all laptop and desktop hard drives, removable media and multi-disk RAID devices. As an industry leader, our data recovery service is officially approved by all leading hard drive manufacturers, including Fujitsu, Hitachi, IBM, Iomega, Lacie, Maxtor, Samsung, Seagate, Toshiba and Western Digital.

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Disk Doctors UNIX Recovery (Solaris) is simple yet powerful and easy to use application for UFS file system supported by Sun Solaris. The software has been designed to provide comprehensive and simple process to access your lost data. The recovery mechanism is completely read-only and doesn???t attempts to write anything to the volume or drive from where it is recovering lost data.

This UFS recovery software must be installed on a Windows machine and the drive containing UFS volume should be attached as a secondary drive to recover lost data. This software helps to recover lost data from different types of storages, which include SATA, IDE/ATA, SCSI, or USB drives. The software has collection of extended algorithms to recover data lost due to virus attacks, accidental disk formatting, software/hardware faults, or disk re-partitioning.
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