Point/Counterpoint - Solid-State Drives vs. Rotational Media
Bill: You know, I just got a new 2.5" drive for my laptop.
Kyle: Yeah? What'd you get?
Bill: Picked up a 7200RPM 500GB disk for $100—half a terabyte, man.
Kyle: That's a lot of storage, but really? 7200RPM? That hasn't been a fast rotation speed for about a decade. Why not get a solid-state drive?
Bill: SSDs are too expensive for my taste, and they don't hold nearly enough data. I like carrying my movies, music and docs around with me—despite the fact that I love cloud storage.
Kyle: I suppose they are a little pricey, but you get a huge performance boost with that price. Plus, it's not too expensive to get a 100Gb+ drive, which should be enough for most of the things you'd need on a laptop. Oh, and nice try throwing the cloud in there to distract me. The fact is, many people are using their laptops as their primary machines these days, and for heavy use, 7200RPM laptop drives just don't cut it. That's especially true if you want to play around with any kind of virtualization. Have you ever tried running two VMs at the same time on a 7200RPM laptop drive? I have, and it's painful.
Bill: For heavy use, 7200RPM drives don't cut it? What crack are you on, man? My machines are plenty fast for what I need. I just priced a 128GB SSD, and it's $475! That's nearly 4x the cost for 1/4 the storage. A 256GB SSD is $679. Crazy prices, man. I can buy a whole laptop for $679.
Kyle: The prices are a bit high right now, but they keep coming down. Sure, you can buy a whole laptop for $679, or for $1k, you could buy a laptop with twice the performance. With the multicore and other high specs in machines these days, the disk is definitely the bottleneck. If you solve that problem, you can take advantage of the rest of the machine.
Bill: Not to mention there's the whole “not fully baked yet” issue with the technology. Do you remember Intel's boo-boo when it had some firmware glitch that killed performance and ate your data? Rotating media isn't perfect, but its issues are known. I love the smell of baked data in the morning—just like when I tried XFS at your insistence.
Kyle: That's true, rotational media has never had a firmware problem nor issues that resulted in data loss. They certainly don't have any problems in portable devices like laptops if they get any kind of shock. The fact is, it's common now for laptops to have at least two cores, if not more. Parallel computing is not just the future, it's how we use our computers today, and you need storage that doesn't choke with multiple processes accessing random sections of disk.
Bill: This from a guy who was running a single-core laptop until just a few months ago—with a 1.8" disk, if I recall.
Kyle: Yeah, in fact, it was a 1.8" disk, a 5400RPM one (the fastest they made at the time), until I upgraded it to SSD. The old rotation media in the laptop just didn't cut it.
Bill: I didn't say they haven't had issues. But, SSDs were touted as invulnerable and the greatest thing since sliced bread until that point.
Kyle: I'm sure you still listen to music on vinyl, so no wonder you prefer your storage to use the same technology. At least if you bump your record player, you risk only a scratch and not a head crash.
Bill: Hey, I don't listen to vinyl. Are you not paying attention to our own column? I listen to music on my iPhone, man. And, not all SSDs are super performance-oriented. I have a Netbook with an SSD in it, and the thing is the biggest POS I have ever used.
Kyle: I agree not all SSDs are equal. You have to do a bit of research, just like with video cards or any hardware purchase where performance matters. Oh, and thanks for the lessons on data integrity. I must be remembering some other friend of mine who trashed his rotational laptop drive by putting his magnetic palm pilot case too close to it.
Bill: Yes, I killed my disk. Like you've never smoked a piece of gear. It's funny how recently you got on the performance bandwagon too. I remember you telling me that “a single 1.2GHz core was fast enough”, and “I'm willing to pay the penalty for a slow 1.8" disk for the portability”.
Kyle: Yeah, I was willing to pay the penalty for portability. Now my main portable computer is an N900, so I can stand to have a slightly larger laptop that can handle a larger drive. Recently, I've tried using it for virtual machines, and the 7200RPM drive it has is a pain. It just chokes when you have too much going on. I'm wishing I had invested in an SSD when I first spec'd it out, but I figured I'd give the 7200RPM drive a chance first.
Bill: Regarding g-forces and rotating media, the new accelerometer-based tech has helped disks survive crazy things, and the smaller, lighter head shave helped too. Anytime you have IO contention, you'll have performance issues. Faster disks move that out. But really, it's not like two VMs are unusable—I have two going on my laptop routinely. Matter of fact, one of them is how I access e-mail (don't ask, I have some totally bizarre corporate antics to put up with).
Kyle: I'm glad they've made the tech equivalent of a seat belt and airbag to save your rotating media, but I'd rather it not be a problem in the first place. I mean, even the iPod figured out SSDs were the way to go years ago. I'd figure if it's good enough for Apple, it'd be good enough for you. The bottom line for me is that my laptop is more than just a portable computer, it's my main computer for anything resource-hungry these days (I use a pocket computer for everything else). So performance matters, especially when I have multiple processes accessing different parts of the disk at once. SSDs are the future, and although they are a bit pricey now, the price keeps coming down and will continue to come down.
Bill: Hey, it's all about price/performance ratio. SSDs appear to have about an 8x premium, and that's not something I'm willing to pay when a 7200RPM disk gets the job done for me and allows me to carry all the data I could possibly want and more. SSDs are the future—yes, I grant you that. But, we live in the present, and I'm totally fine with letting early adopters like you find the data-eating bugs and drive the cost down to the point where it does make sense for me to buy. Today, my money's still on good-old rotating media.
Kyle Rankin is a Systems Architect in the San Francisco Bay Area and the author of a number of books, including The Official Ubuntu Server Book, Knoppix Hacks and Ubuntu Hacks. He is currently the president of the North Bay Linux Users' Group.
Bill Childers is an IT Manager in Silicon Valley, where he lives with his wife and two children. He enjoys Linux far too much, and he probably should get more sun from time to time. In his spare time, he does work with the Gilroy Garlic Festival, but he does not smell like garlic.
Kyle Rankin is a VP of engineering operations at Final, Inc., the author of a number of books including DevOps Troubleshooting and The Official Ubuntu Server Book, and is a columnist for Linux Journal. Follow him @kylerankin.
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