What Hard Drive Should I Buy?

Because Backblaze has a history of openness, many readers expected more details in my previous posts. They asked what drive models work best and which last the longest. Given our experience with over 25,000 drives, they asked which ones are good enough that we would buy them again. In this post, I’ll answer those questions.

At the end of 2013, we had 27,134 consumer-grade drives spinning in Backblaze Storage Pods.

Why do we have the drives we have? Basically, we buy the least expensive drives that will work. When a new drive comes on the market that looks like it would work, and the price is good, we test a pod full and see how they perform. The new drives go through initial setup tests, a stress test, and then a couple weeks in production. (A couple of weeks is enough to fill the pod with data.) If things still look good, that drive goes on the buy list. When the price is right, we buy it.

We are willing to spend a little bit more on drives that are reliable, because it costs money to replace a drive. We are not willing to spend a lot more, though.

When I say “low write” I mean lifetime, not on average. Matter of fact, newer SSDs handle the swap files without issue and no degradation overall. “Low write” generally means sequential, so you don’t want to re-write the same sectors over and over again or you wear out the gate and eventually the transistor stops working.

They’re not as delicate as you might think. I run my Windows desktop on 2 OCZ SSDs including the swap file, but since I have 12 GB of RAM, the swap file is not used very often. As long as you have defrag turned off, as it is with most modern operating systems using SSDs, and the “fetch” programs are turned off in MS Windows, your SSD will last longer than you’ll likely need.

Nowadays, SSDs are the most noticeable upgrade to a computer. You can have the fastest, most up-to-date processor, RAM, and graphics cards, but if you’re using old-school spinning disk, your bottleneck is always going to be your disk.

Just an update: Although there has been a refutal recently, http://www.enterprisestorageforum.com/storage-hardware/selecting-a-disk-drive-how-not-to-do-research-1.html, I have been monitoring several tech sites and they do not agree with the refutal. Most, if not all of the users out there have experienced pretty much the same results as previously presented by the BackBlaze people -essentially, Hitachi is very good, then WD, and Seagates have some issues that need to be addressed. As in some people stating they have a failure rate approaching 25 percent over a short period of time.

What you should buy are enterprise hard drives. Hitachi Ultrastar and Western Digital RE models. You'll get a better built, longer lasting drive with longer MTBF (mean time between failures)fewer errors and better performance.

In the week or so since the report was first published, several techies have posted on other sites as well that their experiences are pretty much identical with the results posted here. Your recommendations follow their indications, and we should all take note. I will definitely be looking much closer at the manufacturor of any new drives purchased in the future and plan on concentrating on Hitachi as much as possible.

You might be interested in one user's experiences:

"It really doesn't matter what the accumulated knowledge over the intervening years says, the facts remain that for this user, Blackblaze, the results were the results, and it happened to match what the industry already knew.

Their results: Hitachi has the lowest overall failure rate (3.1% over three years). Western Digital has a slightly higher rate (5.2%), but the drives that fail tend to do so very early. Seagate drives fail much more often — 26.5% are dead by the three-year mark."

I think I would be very cautious about using drives other than the best for critical purposes.

For those of us who already possess one or more Seagate drives, now might be a very good time to start lots of backups going.

Another user's comments about the report:

"This article states everything anyone competent already knew. Consumer drives come rated for a lighter workload than enterprise.

Duh? That's the point - it's a cost:reliability tradeoff. With "enterprise" drives being 1.5x+ the expense, for uses like Backblaze where you can survive multiple disk failures with ease it's a no-brainer.

I also got "burned" by these Seagate 1.5TB disks. By *far* the worst drives we have in production (~300 or so these days), and they have had an annual failure rate around 20% since the day they were put into service. Other consumer drives don't even come close to that metric, but are rated similarly.

I actually like Seagate - every disk manufacturer has problematic models from time to time. No big deal, we knew the risks when we bought them. However, the data Backblaze published is completely validated by our own internal data. It's a drive model to avoid when at all possible. Most of our disks have a less than 5% annual failure rate, but this specific model is close to, or over, 20%. That's a major difference.

This article just states the obvious. Consumer drives generally fail earlier under heavy loads. This is not interesting, it's a known tradeoff anyone with a high school degree can figure out for themselves by looking at cycle ratings and MTBF. The only thing I care about for this workload, is if my failure rate exceeds the savings I get from utilizing the lesser drives. The answer has thus far (even with 20% of drives failing each year) been a resounding yes.

There is a difference between consumer drives, data like this is *great* to have published as it can add to your own data and you can compare notes. Will I make a buying decision based off it? Probably not. But it will certainly be one data point of many when it comes time to buy more disk. Known issue? I don't care. All I care about is if the drive works or not, and this particular Seagate model does not. The author of this article completely glances over the fact Seagate admitted to the issue, but did absolutely *nothing* to make it right for their customers essentially blaming them. This fact is what bothers me the most, not the fact they had a problematic drive model - and will likely be the largest factor when it comes to my evaluating Seagate products in the future."

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.