How Does RAID Work


Did you know that there’s a relatively simple and inexpensive way to ensure that you always have a full, up-to-the-minute backup of your desktop computer’s hard drive?How does raid work

Well, there is. All you have to do is install a second hard drive in your computer and change a setting in the BIOS to enable RAID 1. What is RAID 1 you ask?

The acronym RAID stands for Redundant Array of Independent Disks. There are several “RAID Levels” that one can use, but when two drives (or SSDs) are used in a RAID 1 configuration, a copy of everything that’s written to the primary drive is also written to the secondary drive. This in effect maintains a 100% up-to-date backup of your data at all times.

This “mirroring” is done instantaneously, ensuring that both drives ALWAYS contain exactly the same data. That way if one hard drive fails, you lose no data whatsoever and your downtime is minimal because the second drive is already in place and ready to go.

To get everything back to normal, simply replace the failed drive with a new one and then reboot the computer. In most cases, the RAID controller will automatically begin mirroring the contents of the old RAID drive onto the new drive as as soon as the PC finishes rebooting.

As you can see, two drives in a RAID 1 configuration make maintaining a current backup of the primary drive about as easy and hands-off as you can imagine. But there are a few caveats to be aware of:

1 – Backing up your hard drive via a RAID 1 configuration isn’t 100% fool-proof. If your PC gets destroyed in a fire or both RAID drives get fried by a lightning strike, you will have no backup to use when you replace the PC. For this reason it’s strongly recommended that you make periodic remote backups as well via a service such as Carbonite or Mozy.

If you want 100% protection from loss of data, the use of an alternate off-site backup service is a must! The RAID 1 method of data backup should be used only for the relative convenience and lack of downtime provided should a single drive happens to fail.

2 – While the two drives do not have to be identical, the total available storage capacity of the RAID configuration will be limited to the capacity of the smallest drive. The speed at which data is written to the drives will also be limited to the speed of the slowest drive.

3 – Using two drives in a RAID 1 configuration will result in small (but usually negligent) performance hit since the same data must be written to two separate drives instead of just one.

4 – Not all computers are equipped to support RAID, but virtually all recent desktop PCs are. Consult your computer’s user manual (or the motherboard manual) to find out whether RAID is supported or not. If it isn’t, you’ll need to purchase and install an inexpensive RAID Controller Card.

Setting up a RAID 1 automatic backup system on your desktop PC isn’t very complicated at all once you have ensured that it is equipped with a RAID controller. Simply install a second hard drive that’s at least as large as your current drive, then enable RAID 1 in your PC’s BIOS hard drive controller settings (consult your PC or motherboard’s user manual for instructions).

Bottom line: Adding a second drive to your system in a RAID 1 configuration is a great way to ensure that you always have a complete backup ready to use immediately after a hard drive failure without having to “restore” your data from a traditional backup.


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