Do We Need 7200 RPM Drives?
December 12, 2011 2 Comments
Right now, all of my personal computers (yeah, I have a lot) now boot from SSD. I have a MacBook Pro, a MacBook Air, and a Windows 7 workstation, all booting from SSD. And the ESXi host I have will soon have an SSD datastore.
And let me reiterate what I’ve said before: I will never have a computer that boots from spinning rust again. The difference between a computer with an SSD and a computer with a HDD is astounding. You can take even a 3 year old laptop, put an SSD in there, and for the most part it feels way faster than the latest 17 inch beast running with a HDD.
Yeah yeah yeah, SSD from your cold, dead hands
So why are SSDs so bad-ass? Is it the transfer speeds? No, it’s the IOPS. The transfer speeds in SSDs are a couple of times better than an a HDD, but the IOPS are orders of magnatude better. And for desktop operating systems (as well as databases), IOPS are where it’s at. Check out this graph (bottom of page) comparing an SSD to several HDD, some of which run at 15,000 RPM.
As awesome an unicorny as that is, SSD storage still comes at a premium. Even with the spike in prices caused by the tragic flooding in Thailand, SSDs are still significantly more expensive per GB than HDDs. So it doesn’t make sense to make all of our storage SSD. There’s still a need for inexpensive, slow bulk storage, and that’s where HDDs shine.
But now that we have SSDs for speed, 7200 RPM is overkill for our other needs. I just checked my iTunes directory, and it’s 250 GB of data. There’s nothing that MP3 sound files, HD video files, backups, etc. need in terms of performance that would necessitate a 7200 RPM drive. A 5400 RPM drive will do just fine. You might notice the difference while copying files, but the difference won’t be that great when compared to a 7200 RPM drive. Neither are in any position to flood a SATA2 connection, let alone SATA3.
Even with those USB portable hard drives which have 5400 RPM drives in them, it’s still more than enough to flood USB 2.0.
And this got me thinking: How useful are 7200 RPM drives anymore? I remember taking a pair of hard drives back to Fry’s because I realized they were 5400 RPM drives (I wasn’t paying attention). Now, I don’t care about RPMs. Any speed will do for my needs.
Hard drives have been the albatross of computer performance for a while now. This is particularly true for desktop operating systems: They eat up IOPS like candy. A spinning disk is hobbled by the spindle. In data centers you can get around this by adding more and more spindles into some type of array, thereby increasing IOPS.
Enterprise storage is another matter. It’s not likely Enterprise SANs will give up spinning rust any time soon. Personally, I’m a huge fan of company’s like PureStorage and StorageFire that have all-SSD solutions. The IOPS you can get from these all-flash arrays is astounding.