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To be clear, there are definitely times when RAID is a good route. I will get into that later, but I need to start by saying that I am not talking about enterprise servers. That is a completely different type of computer. I am talking about home desktops, enthusiast computers, and professional workstations.
What is the Problem?
The underlying problem with RAID is the fact that by using it, you are making your computer significantly more complicated. Not only are you now relying on two hard drives to work properly, but you are also relying on a much more complicated controller (the RAID controller). If any one of those items has a problem, the array fails. If one hard drive has a problem even for a moment, you have a degraded array on your hands. At that point, you are relying on the RAID controller for error correction and array management, and the fact of the matter is that all (yes, all) RAID controllers onboard a motherboard are low quality. They have been added to the motherboard as an afterthought — a feature added simply because the manufacturer knows that if they add any feature they can, they’re more likely to sell their product. At at a time when nearly every modern motherboard has built in RAID, they have to offer it just to be considered as feature rich as their competitors.
RAID1 (mirroring) for Data Loss Protection
|Hard Drive||# Units Sold||Failure Rate|
|Seagate Barracuda 7200.9 250GB SATAII||280||3.21%|
|Seagate SATA Barracuda 80GB||271||2.58%|
|Western Digital SATA Raptor 74GB||592||2.03%|
|Seagate Barracuda 7200.10 320GB SATAII||202||1.98%|
|Seagate Barracuda 7200.9 160GB SATAII||265||1.89%|
|Seagate Barracuda 7200.9 80GB SATAII||403||1.74%|
|Western Digital ATA100 80.0GB WD800JB||290||1.72%|
|Western Digital SATA Raptor 150GB||278||1.44%|
When I look at those numbers I see excellent reliability. Specifically, the Western Digital Raptor hard drives impress me. We sell a huge amount of those drives, and have only had a handful fail. In fact, two of those failures were our fault — one we wired incorrectly and fried, and the other we dropped on the concrete warehouse floor…so technically, the Raptor failure rate should be a bit lower. Impressive! Neither of these damaged hard drives ever even left our facilities, obviously.
Unfortunately, it is not as clear of a number when it comes down to how many RAID failures there have been. Since it is not a black and white failure issue, I do not have hard data. However, at the agreement of our support staff, I estimate that anywhere from 25% to 30% of our customers with RAID will call us at some point in the first year to report a degraded RAID array or problem directly resulting from their RAID configuration. Granted, a failed RAID1 array does not mean data loss, but it certainly means a long, frustrating hassle. On the other hand, a single hard drive will often give warning signs before failure, so that scenario doesn’t necessarily mean data loss either.
The real question is: Is RAID1 really worth being 15-20 times more likely to have a problem? Keep in mind, RAID1 does nothing to protect you from:
- Accidental deletion or user error
- Viruses or malware
- Theft or catastrophic damage
- Data corruption due to other failed hardware or power loss
So if you are going with a RAID array to protect your data, just look at the numbers, and make an informed decision. My personal recommendation is that if 3% or less is too high a risk of possible data loss, then get yourself an external SATA or USB hard drive, and run a scheduled backup. Not only does that get you nearly all the protection of RAID1, but it also protects you from the four things above. This leaves you even more protected in the end. Not only that, but it vastly simplifies your computer, leaving you literally 15-20 times less likely to have frustrating problems with your data storage.
RAID0 (striping) for Performance
Video editing is a good example of when RAID0 might make sense. Now, you still need to be sure that the speed of the hard drives is the right place to focus. For example, if you are editing a video, and when doing so your CPU usage is pegged at 100%, then you can be fairly certain that moving to RAID0 will not be a help, because you’ll still be limited by your CPU. Therefore, video editing alone does not mean RAID0 will be useful…it has to be video editing in which your CPU or memory is not the bottleneck, which honestly is very uncommon. My personal recommendation — do your homework. Do not take on the hassles of RAID unless you know it will be a help. Go into your research with the knowledge that it is actually very uncommon for RAID0 to be faster in desktop usage.
Don’t take my word for it! Storagereview.com, an authority in hard drive performance analysis and discussion, has a whole page talking about RAID0.
The other time when RAID can make sense is if you need an extremely large volume of space. RAID0 or RAID5 would be able to let you combine drives together. If you’re working with HD video and need to be able to save 2-3TB of data, then a RAID array is necessary to have a working space that large.
Other Types of RAID
My conclusions are based on benchmark data, as well as over six years running a custom computer company, a company whose target market is made up of all the people that are targeted by the hype of RAID. If you have anything to add, please email me! I’d be happy to consider adding it to this article.