Here's a typical hard disk drive (HDD):
This is where your data spends most of its time.
The amount of data you can put on each HDD has gotten exponentially better over time. For example, this chart (all credits: Wikipedia):
shows hard drive capacity in GB over time.
Back in the mid-1980's, HDD's were sized about 10MB. By the mid-1990's they were up to about 1GB, an increase of 100 times. Now they're up around 1TB, an additional increase of 1,000 times. Amazing, particularly when you consider that the average HDD was also shrinking in physical size over that time:
Right: an older 5 1/4" HDD with 110MB; left: a 2 1/2" HDD with 6.5GB.
Suppose the size of your main customer database is 1TB. In the mid-1990's, it would have required about 1,000 HDD's to store the data, and today you can put it all on a single HDD: it's wonderful, yes? Well, maybe not. The problem is using your data.
The problem is simple to understand. Here:
is the inside of a HDD. Your data is stored on platters. It's read and written by a head, which is at the end of the long arm that ends near the center of the platter. In order to read any piece of data, the arm has to position the head on the right track of the platter (i.e., move it towards the edge or towards the center of the platter), and then has to wait until the spinning platter brings the data to the head.
Here's the killer: these times (called seek times) haven't improved much in the last 25 years! In the mid-1980's they were around 20ms; today, most HDD's are around 10-15MS, and the very fastest are around 3ms, around a 7X improvement at best.
These trends (more data in less space, and unchanging seek time) are likely to continue.
Improvements in HDD's since 1980's:
Speed 7X
Capacity 100,000X
The bad news isn't over yet. Remember how your customer data used to take 1,000 HDD's? That meant that you had 1,000 HDD's all available to read and write your data. Now you've got just one -- and it's hardly any faster than HDD's were 25 years ago!
What does this mean? If you want to not just keep your data, but also access and update it, you've got a big problem today, and it's getting worse.
How are people responding to this situation? Simple: they are turning to SSD's. SSD's solve the speed problem! But, as provided by most vendors, SSD's introduce a whole host of new problems. Today, storage buyers confront an extremely unpleasant choice: buy extremely expensive SSD's that lack fundamental storage features, or buy affordable HDD's that simply aren't fast enough. Yuck.
There is an alternative. It's a good one. It combines everything you like about HDD's with the speed of SSD's in a novel hybrid combination. I can't stop thinking about about it. Check out the Xiotech hybrid ISE.
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