RAID Hard Drives
Posted By On November 21, 2007 @ 1:49 PM In File & Disk Management | No Comments
What is a RAID hard drive? I’ve been hearing about them quite a bit lately, but I have no clue what they are or if I should really consider using one. Please explain!
Basically, in a RAID system, two or more inexpensive hard drives are put together to create one single large capacity storage device that also offers an enhanced performance. When the RAID system was first introduced, it was mainly used by large businesses that needed a large amount of data storage space. I mean, yes, it can protect you against data loss if one of the hard drives fail, but it’s not really meant to be used as a backup solution for the average user. But, in the last couple of years, RAID has increased in popularity and it’s starting to be used in more personal computer systems.
Now, RAID can actually be classified into two different categories: hardware RAID and software RAID. On the hardware side of things, the storage system created by the two hard drives is managed separately from the host computer, which then shows up as a single drive to the computer. The host computer doesn’t even really have to know that a RAID system is being used. As far as hardware goes, some of the RAID systems are put into place with a special hard drive controller card or the RAID functionality can be built right into the motherboard.
On the other hand, for the software side, the host computer handles everything. It’s what makes the RAID system look like one single hard drive. Unfortunately, this method does decrease the overall performance of the RAID system a little bit, because it functions by using some of the system’s memory and CPU cycles, which makes it completely dependent on the CPU.
With all of that said, there are six different levels of RAID:
1.) RAID 0 – This level requires a minimum of two disks. It does provide improved performance, but it doesn’t account for data repetition or failures. With this level, data striping is used so that the data is all split up onto the two disks. So, yes, this method does work at a very high level of performance, but if either of the drives fail, all of that data will be lost for good. I guess there’s always a price to pay.
2.) RAID 1 – This level is a mirrored set of two disks in which the data is replicated to separate hard disks in real time. It’s done that way to ensure continuous availability, currency and accuracy. This level does provide fault tolerance in case any disk errors or failures occur.
3.) RAID 3 and 4 – These two levels are combined together in a set of three or more disks. One of those disks is mainly used for error checking, so if that particular one fails, the other two will be able to continue working without the error checking function. On the other hand, if one of the data drives itself fails, all of the RAID data will be lost.
4.) RAID 5 – This level is also a set of three or more disks, but for this method, the error checking disk is split up between all three drives. In that case, one single drive failure can be handled, but if more than one drive fails, all of the RAID data will be lost.
5.) RAID 6 – This last level is a set of four disks (minimum) and two of them are used for error checking only. With that being multiplied, the RAID system can still operate if two of the other drives fail. Once one of the drives is replaced, the data can still be saved and it is then split up between all of the RAID drives.
Now, the level of RAID you should use depends on what you do with your computer. For example, if you do a lot of video processing or gaming, you’re going to want a more reliable RAID system, such as level 5 or 6. If you do a lot of banking and online shopping with your computer, you will want a safer RAID system, so the mirrored option of level 1 may be your best bet. It all depends on your computing activities.
RAID systems are available for Windows, Mac OS X and Linux operating systems. Now, if you’re interested in getting one for your computer, I would definitely suggest looking into it a little more. You can certainly use this tip as a reference, but you’ll want to do some of your own researching as well. RAID is an inexpensive way to go, but you have to make sure it’s going to work well enough for you and your computer. I must admit though, it’s a very interesting concept and if any of you use RAID or plan to in the near future, I’d love to hear about it!
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