Tuesday, 21 May 2013

It's a Raid!

As we become more and more dependant on our computer systems, it becomes more and more apparent the need to keep backups.

While the cost of external back up drives is getting lower and lower, there is a constant risk of "forgetting" to take regular backups of your data which only becomes apparently when your main system crashes, or the drives fail.

Is there anything we can do, which happens quietly as we work ? Yes.

RAID is a system of using multiple drives to give data redundancy. This means that you end up with copies of data occurring as you work and can give almost instant safety.

The level of RAID largely depends on the space you have in your computer tower, and the budget that you have. But even the simplest systems could support the basics RAID settings that would give most users a level of comfort.

We'll discuss just 4 levels of RAID. There are many others, but the 4 should help most home users and some smaller businesses too.

RAID 0 uses a system of STRIPING the data. This means that if you had 2 x 500gb drives you'd have about 1000gb (1TB) of storage space.  The plus side of this is that half of the data is kept on one drive and the other half is kept on the other. This gives you twice the space and double the speed as both parts of the data can be accessed at the same time.  The down side is that if one drive fails, you lose all your data.

RAID 1 uses a system of MIRRORING the data. This is much safer as the data is stored on both drives at the same time. The access time is slower as the computer has to write the data to two drives concurrently, and you don't get any more space than just one drive. But if one drive fails, you have a second drive with exactly the same information on. You can then purchase a new drive to replace the failed one and it will copy the information across onto the new drive - thus mirroring the information once more.  For low budget, this is a good system as it only costs the price of the additional drive and most computer towers would have the space to house it.

RAID 5 uses a system of Striping with Parity. You need 3 drives for this to work. This means that the data is spread across the three drives but a "parity" bit is written away too, which means that if one drive fails, you have enough data across the other two to rebuild the information when you install a new drive.  It takes a while to rebuild, but it gives you the speed as well as low cost backup options.

RAID 10 uses MIRRORING and STRIPED together. You require 4 drives for this to work.  The system will pair of two of the drives and stripe the information across the other pair. You then get the speed of striping as discussed in RAID 0 but with the redundancy coverage of RAID 1.  The down side is that you have to invest in 4 drives to make this system work. It all depends on the importance of speed and data recovery.

This is not a conclusive article on the benefits or negative outcomes on RAID. There are more in-depth discussions across the web. But we wanted to give a quick overview on the facilities available to users as data becomes more and more important.

Have fun and remember.. BACK IT UP!!

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