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The Challenges of Recovering Data from RAID Hard Drives

Written by oneself on 5:28 AM

By: Rob Parker

A “Redundant Array of Independent Drives” is a popular technique today for people working with several hard drives at once. RAID is a data storage scheme which divides or replicates data among the hard drives used, and is thus capable of offering higher data reliability and shorter response times than other schemes. This system has been in use for some time in applications that are considered non-critical.

The reason for the use of the scheme within non-critical elements of a business is that unfortunately, when one drive in a RAID system fails all of the data stored on the entire array may also be corrupted, or simply rendered inaccessible. For a business without knowledgeable support, this can be devastating. The first challenge to any recovery effort will be the reinstatement of data on not just one, but all of the drives involved in the system. The higher the level, the more complex the data recovery process becomes. Each piece of data on each drive is important, and a recovery system that ensures complete recovery is key.

When it comes to the actual recovery process, the person using a RAID scheme has a few options. Someone trained in the implementation of RAID and its applications could recover the data from the drive, as long as the data required is on the drive involved at the time of the failure. Odds are the user will have to call for help; that means two choices.

First of all, you could contact the manufacturer’s support department. It is likely that they will be able to get your system up and running again, but like many support systems the recovery of your data is only a secondary objective. Basically, the manufacturer will assume that you have backed up your important data in a suitable fashion and the support staff are trained to operate under this assumption. The manufacturer cannot be expected to take responsibility for your data stored on its product.

The second option, and the best one open to the user, is to call in the services of a company that is trained in all manner of data recovery methods, and specifically one that has experience with all the levels of RAID storage. This service can be hard to find, since recovery issues and systems requirements are quite specific, but there are times when it pays to seek out the experts.

RAID schemes may be more reliable when it comes to data management, but in the event of a failure the challenges loom large. Getting the data from each system involved and ensuring that data recovery are at the heart of a support system are two of the most critical issues that a user of a RAID system will face in a failure, and it’s important to find individuals who can handle the challenge.

You have a Raid data disk system, and of course the time when you don't back it up is when it crashes, now it's time to face the challenges that follow.
Many software solutions promise that you can recover data on your own, but data recovery is often not possible when there has been internal damage.

Article Source: http://www.eArticlesOnline.com

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Backups for Business: RAID

Written by oneself on 5:01 PM

Intel Matrix Storage RAID can be an important part of a multifaceted approach to protecting your business data.

Richard Morochove

There are two types of businesses: those which have experienced the gut-wrenching loss of valuable computer data, and those which will.

Unfortunately, not all businesses take adequate precautions to protect their operations from data loss. According to a recent Office Depot publication on disaster preparation strategies for small businesses, 20 percent of them do not back up their data. The study states that a company that cannot access its business data for longer than 48 hours is unlikely to fully recover from the outage.

Home Backups not Suitable

A weekly or monthly data backup may be entirely adequate for a home PC, but it falls short when it comes to protecting business data. While a home user may be inconvenienced by losing a few days' worth of e-mail messages and having to wait three or four days for a PC to return from the repair depot, a business will suffer more severe financial consequences.

If a business has no way of entering customer sales orders, issuing invoices, or managing its operations without access to its computer data, any outage that lasts more than a few hours will deliver a blow to the bottom line. How can you protect your business from this loss without spending a fortune?

The Perfect Data Backup

A perfect data protection technique should back up data speedily, conveniently, automatically, and at a reasonable cost. It should safeguard against all reasonably possible causes of data loss, from the failure of a single hard drive to a fire that destroys the office and the computers within it.

A RAID (redundant array of inexpensive, or independent, disks) setup can back up data quickly, in the blink of an eye. But RAID doesn't protect against accidental deletion of data, nor does it safeguard against a disaster that destroys an entire computer, such as a flood.

Daily backups to a tape drive or to an external hard drive provide some protection against accidental deletion of data. However, this technique backs up less frequently and requires more time to complete--sometimes several hours--than RAID. Also, it still doesn't help if a disaster destroys your building.

Periodic rotation and transport of backup tapes or external hard drives to offsite storage will protect against theft or destruction of the premises. But physical shuffling of storage media is neither convenient nor automatic.

Internet-based systems that transmit backups to remote data centers are convenient and can be configured to operate automatically. However, if your business has dozens of gigabytes of important data, a full backup can take days to complete, even over a broadband Internet connection. Monthly service fees can be pricey.

Combining Backup Techniques

If there's no one perfect data backup technique, do you just throw up your hands and hope a disaster will never strike?

Not at all. You can build a good data backup system by using more than one technique. This belt-and-suspenders approach to data protection relies on the strengths of one backup technique to offset the weaknesses of another.

Implementing multiple backup techniques will cost more than using just one. However, the value of your business data will almost certainly justify the additional cost.

Fast, Affordable RAID

I'll be addressing different backup options in more detail over several columns. But for immediate and constantly renewed data backup I can think of nothing better than using a RAID array of hard drives to store both data and important programs on your server or PC.

RAID is less expensive and easier to set up than ever. Until recently, you needed to purchase a special card to set up a hardware-based RAID array. In addition, migrating to a RAID array from an existing hard drive involved a not-insignificant risk of data loss.

Now, many new PCs come with a drive controller with RAID capabilities, whether or not it is advertised. Computer makers don't often undersell and over-deliver in this way, but I believe some do so in this case because they are concerned about the cost of supporting RAID migrations.

Intel Matrix Storage

Intel's hardware-based implementation of RAID works with recent versions of Microsoft Windows including 2003 Server, XP, and Vista. A number of popular hard drive controllers made by the chip-making giant support the technology.

To implement Intel's RAID, you must install at least one additional hard drive and load Intel Matrix Storage Console management software, which you can download for free from Intel's Web site. The site lists the supported drive controllers and includes complete installation instructions.

Fault-Tolerant RAID

A comprehensive discussion of all RAID options is beyond the scope of this column. But make sure to select a method that offers fault tolerance through data redundancy, such as RAID 1 (often called mirroring), RAID 5, or RAID 10. RAID 0, sometimes called data striping, provides no safeguards for your data; rather, it's intended to improve performance.

Implementing RAID 1 requires adding an additional hard drive of equal or greater storage capacity than the drive you already have on the PC or the server you wish to back up. If you have one 250GB hard drive, for example, you'll need to install another with at least 250GB capacity. These days, such drives are relatively inexpensive (see our latest top 10 internal hard drives chart).

Intel's Matrix Storage Console makes it easy to migrate from a standard single hard drive to a RAID 1 array with two hard drives, within 3 hours. Data on the existing hard drive is preserved. You can continue to use the PC during the RAID migration, though operations will be slower until the process is complete.

RAID 1 can noticeably improve data-retrieval performance for dual-core PCs, since information can be retrieved from either mirrored hard drive. There is no significant improvement when saving data, however. The only RAID migration drawback I have noticed is that you may need to reregister some apps, such as Adobe's Creative Suite.

When a Good Hard Drive Goes Bad

If one hard drive crashes in a fault-tolerant RAID setup, its data is safely stored on the other hard drive(s) in the array. It's a simple matter to restore normal operations.

Recently my computer froze after one hard drive failed in a RAID 1 array. Rebooting the computer required more time than usual, almost 15 minutes. However, the second hard drive took over and the computer operated normally, with no evidence of data loss.

To restore the data protection offered by RAID, I needed to install another hard drive to replace the failed device.

RAID Rocks

Performance-wise, it's hard to beat the ability to return to normal computer operations after a hard drive failure in just 15 minutes. My added cost for RAID protection was about $100 for the second hard drive and cables.

I will discuss complementary backup techniques that offset RAID's weaknesses in a future column.

Richard Morochove is an IT consultant and writer. Send him questions about using technology in your small to mid-sized business via e-mail. PC World may edit your query and cannot guarantee that all questions will be answered.

source:www.pcworld.com

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