In my role here at Xiotech I get to spend a lot of time with prospects as well as customers. It’s probably why I love my job so much. My wife seems to think it has more to do with my A.D.D. (Attention Deficit Disorder) and the ability to change topics and discussions on a daily basis then it does anything else. She’s probably right; at least she likes to point out just how right she typically is!! But that’s probably a separate blog posting 🙂 So back to my role and the blog topic at hand.
Have you heard of the phrase “Performance Starved Applications” or PSA? Hopefully this term is not new to you. PSAs are simply applications that are not performing correctly due in large part to two things. First, the customer purchased a solution that the vendor failed to size correctly; or if it was sized properly, the customer failed to understand the caveats once it was deployed. What sort of caveats might this be? In typical SBOD (Switched Bunch of Disks) arrays, as the storage system fills up, the performance drops like a hammer. This isn’t just a one vendor issue. Have you noticed that a lot of storage vendors use the same parts to build their arrays? For example, place a Clariion, EVA, FAS, Storage Center, Magnitude 3D next to each other. About the only difference is the logo and the software loaded on the controllers. In most cases they are using the exact same drive bays, shuttles and drives. So, they all suffer from the same issue and they all have a similar caveat when it comes to just how full you can load up their system. The industry has settled on about 75%.
So hopefully we all agree, as the storage system fills up, the performance goes down at just about the same interval. To give you an example, a typical enterprise-quality Seagate drive can produce about 300 “typical” IOPS empty. At 50% full, it drops to about 50% of the performance or 150 IOPS, at 75% its closer to 119 IOPS. So, if we can agree on these numbers the rest should make sense. Let’s play with some numbers. So a customer needs 20TB’s of 15K enterprise drives and let’s say we use those new spiffy 300GB 15k Enterprise Seagate drives. Using my “South Texas” math that’s 20TB/300GB drives = 67 Drives. (before you say it, yes I know a 300 GB drive is NOT 300GB but that’s another blog topic all together – not to mention all the sparing needed for that number of spindles, RAID overhead, etc.) so if we take 67 drives times 300 IOPS we get 20,100 IOPS. SWEET. But let’s be realistic, they have no intention of keeping their storage solution empty. So, should we use 50%? That drops the number down to 10,050 IOPS. Not bad, but let’s be really serious here, NO WAY does a customer only use 50% of their capacity right? Most of my customers use 90% of their capacity but we’ll settle in on the industry standard 75% so that IOP Pool would be around 8000 (just in case you were curious on the 90% number it’s 105 IOPS per drive so that would be 7,000). So I put this into a nice graph because I’m a big fan of pictures !!
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So, that’s eye opening.
You essentially paid for 20,100 IOPS but you only get to use 8000. Now think of some of your transactional applications you are running like E-mail and databases and ask yourself “How are they running?” It wouldn’t surprise me if you start to remember a user here or there mentioning that at times their email just sits and waits or database reports that you need take hours to run. Those are what we like to call PSA. And truthfully, most of the time the storage array is the last thing people think of.
So, how can you solve this issue? The typical answer from vendors is “Buy 50% more capacity”. Problem is, you bought more than you need and never use it 🙂 instead, check out one of our Emprise solutions. They are built on our patented (80+ patents) storage system called the Intelligent Storage Element (ISE). The ISE suffers from no such performance degradation. You can check out a couple of YouTube video’s here – http://www.youtube.com/XiotechCorporation
So, the next time you think your applications are running slow or your end users complain of performance problems, you might want to check and see just how full your array is. If you enjoy using 100% of both the performance and capacity you purchased then give Xiotech a call !!!