RAID: Is advisable for Data Backup?

hi there.

I have recently purchased a 250 gb SATA drive, and checked in my motherboard manual about RAID and it's various level. I know that there are various types of RAID (RAID 0, 1, 0+1, 4, 5).

I am thinking of using RAID 1, which writes data to two drives at the same time.

Now my question is is it possible if my primary hard drive fails, can i automatically use the other hard drive?
Also if my primary hard drive fails and i installed a new one, do i have to manually copy the contents of the RAID hard drive to the new hard drive?
And also is this a good backup option?

Answering your first one:
Probably it's not possible. You may have to configure your backup drive to become your primary and then you're all set. The automatic failover switching is for mirrored drives. I could be wrong though. Last time I touched RAID drives was back in the early 90's.

To the second one, yes, maybe, but there are tools for this and it's pretty easy.

For the third, it depends on what type of disaster you are protecting yourself from. This is only good for drive failures. It will not protect you from fire or theft.

Creating backup files can be a tedious chore, and despite nagging articles (like this one), many people still don't do much to protect their data.

Now there are new products that are trying to take the hassle out of backups by delivering high-end business solutions at consumer-friendly prices.

Many companies protect their data by using a technology called RAID (Redundant Array of Independent Disks), which copies all files to a second hard drive as they are created. If the first hard drive ever fails, the second drive contains an up-to-the-minute "mirrored" copy of all the data. The downside is that adding RAID requires opening your PC to install a RAID controller and at least one more hard drive.

To simplify this, several companies are creating RAID external hard drives that connect via USB or FireWire, or over a network.

Hard drive maker Maxtor Corp., for example, has evolved its single-button external drive, the OneTouch, into a two-drive RAID system, the OneTouch III, due in December. Because it copies everything from one drive to the other, the 600-gigabyte version yields 300GB of mirrored storage while the one-terabyte (or 1,000 gigabytes) version delivers 500 gigabytes of storage. As a bonus, the backup software also can synchronize files on multiple PCs.

On the value end, Netgear Inc. has created an empty RAID enclosure, the Storage Central SC101 . It allows consumers to add their own hard drives -- maybe inexpensive drives bought on sale or scavenged from older, obsolete computers. Installing the drives is significantly easier (and less panic-inducing) than opening a PC case.

The least expensive solution is a software program that delivers some of the functionality of RAID without additional controller hardware.

Shadow 2 from NewTech Infosystems Inc., or NTI can also copy selected directories of your PC as soon as they are created, functionally mirroring them onto an external device such as a hard drive, USB key or even an MP3 player like the iPod. Conventional backup software copies data only once a day or once a week, so the backup is rarely up to date with newer, and often the most essential, files.

Shadow 2 also makes it easier to restore your data. Other backup programs store layers of incremental backups in a proprietary format that only they can unlock and recreate. Shadow 2 preserves data in the original format, simplifying and speeding the process of copying your data back.

This is the most likely situation that the user could recover the data fully and without the need to send the RAID system for recovery work. As the RAID is still accessible but without any more fault tolerance redundancy, any failure of next disk will result in complete RAID server failure.

Critical data should be copied out as soon as possible before any rebuild attempt is performed. At this point, the remaining disks making up the RAID volume could be near imminent failure. RAID rebuild process is generally IO intensive and could stress the disks to complete failure. One stands a greater chance to copy out the required data before total failure occurs.

Once the critical data is copied out, standard rebuild process could then be carried out.

Some RAID server is used as application and data server. It may not be sufficient to recover just the data as re-configuration of application may not be possible or too cumbersome. The only feasible option is to rebuild the degraded RAID volume. However, it is advisable that one should backup the disk image from all the working disks before a rebuild is perform.

See how to backup disk image.

In case the rebuild function fails or any more disks fail subsequently, one still has the backup disk image to work on further.

If your data is really important, before you part with your system, you may want to backup the disk image of all the working disks. It is better to play safe so you will always have a backup set to rework in case the original raid server suffered further corruption of any kinds
Carefully take note some of the following info if you have them

Strip block size (normally a multiple factor of 8K) and order of disk elements in which the RAID volume is formed. Such info could normally be found in the RAID BIOS or RAID configuration Manager.
Description of problems
Description of user’s attempt
List of critical data and folders and any special requirements
Label each disk before taking them out and carefully note the corresponding position. This is extremely important if the number of disk elements is approaching 14.
Carefully pack your disks for delivery to recovery expert. Both working and damage disks are needed.

If the RAID volume is not longer accessible, do not attempt any rebuild as such act is meaningless and will only complicate the situation. Rebuild only makes sense if you have a degraded and accessible RAID volume.

Yes, due to the basis of Windows XP in WinNT, the system state files in Windows 9x -- config.sys, autoexec.bat etc., have been replaced by an invisible System Data Set a la NT. The Windows System Restore Points feature and Boot- to-Last-Known Good option in safe mode start is Microsoft's support, but we have found these may not be accessible when windows cannot boot at all, and from booting from the Windows Install Cd (not to mention the documented self-erasing property of system restore in connection with viruses and last-known-good). The install CD only gives access to a useless NT style DOS environment with no access to the system data set backups.

Grisoft supplies a Rescue File copy of system data in its well regarded free and professional AVG anti-virus software, but its bootable diskettes do not include disk drivers for a RAID system. Too bad Acronis can not supply such a feature just to back up this noisome system data. Things which damage this often do not require a complete restore of program files, just deletion of some offending program, typically a driver -- once you can get to a running windows system. (Also booting a windows program without raid drivers damages the RAID array, writing to only one of the disks in the logging folderol and what not, and requires rebuilding the mirror array).

Using a RAID mirror, we can back up the system with Acronis to a separate disk partition (we prefer that to the proprietary Acronis stealthed Secure Zone, so that it can be managed in the event of failures in Acronis software), and with RAID have hardware failure protection. The RAID disk is an alternative to a separate external disk for backup for small systems. They are now included in small Dell computers as a low cost option. The cheaper disk drives making this possible are also more prone to failure -- making RAID advisable (another strange irony of technology economics).

For extreme circumstances we then backup the extra system backup partition to DVD's using the Split Archive feature of Acronis (which does not appear in the manual setting of options in the backup wizard, but must be set as a default option -- a little error Acronis needs to fix) -- or build the backup with the split file feature to begin with.

We have found that Nero can write the backup files to DVD in file mode, but its own backup features splitting files and its partition backup features do not work, and are not compatible with RAID driver requirements as well in their bootable disks. Only Acronis has supplied a bootable recovery disk for extremes -- Norton Ghost could not load the disk drivers, and is inconvenient even if fixed, as it requires a floppy disk install of drivers the same as windows install, every time it is booted. With the Acronis recovery boot disk we can read directly the file copies made by Nero on DVD, and restore the backup partition and the OS from that.

Systems with extensive application data, accounting and so forth, need external hard disk drives for the speed to handle large volumes of data. But just for the OS and programs, the DVD's are reasonable, using only two or three disks at most, and only in extremes as we have the hard disk partition backup which restores in ten minutes or so.

It might be advisable when operating on the primary windows system partition, at least in its initial entirety, operations should be done from the separately booted version of Acronis, so Windows is not modifying the partition while it runs. (Nero would not even allow a partition backup of the active primary partition in which it runs, but amazingly Acronis does it fine even from within Windows). Acronis might clarify whether they use specific tools to accomplish this, in case it is just a coincidence that it works.

We have not found random-access DVD writing (Nero InCd and the like) useful, because it is slow and dependent on that particular software -- regular file writes to DVD can be read by anything, including Acronis for restore. For random access applications use a separate partition of the hard drive protected by RAID, or an external hard disk.
The superior quality DVD-Ram disk media system (used on Panasonic DVD recorders) does not appear popular either, and so is not recommended for long-term storage; very few drives support it, and there could again be software dependencies -- another betamax VCR situation.

One common practice is installing Windows in one small partition and all applications in another partition. Yet applications may also allow redirection of application data to yet another partition, and all the program code and windows have become tightly integrated and cross referenced in various indexes. So I am not sure of the advantage of this, it may be a legacy of older system architecture, and it could even lead to unsychronized code and OS partition content.

It would be helpful if Acronis would write a guide to system design and backup methods addressing the needs of different size systems and operations, or find a literary reference on such they could give. There is too much mystery surrounding this for the complexity Microsoft has created in systems even for simple home use, with the vulnerabilities created by the Internet

Hi, you'd better replace the bad one with the second drive. There's no need to manually copy the contents of the RAID hard drive to the new hard drive.
But to ensure the safety of data, u may need do some backup in case of any other unpredictable crash on your both drives, especially for some virus attack. This page may be helpful for you.