We’ve spoken a lot about the Nasuni Filer’s key features and today we’ll explore how our approach to pricing also sets us apart from the competition. We’ve written previously about the benefits of providing a single bill for our customers. We’ve even mentioned that we level the CSP charges down to a flat cost per GB. This might sound unimpressive, but in reality, cloud pricing isn’t always as simple as advertised. So, what is the cost of a GB in the cloud?
Users of the Nasuni Filer may not be aware, since Nasuni takes care of this mess for them, but the CSPs all have different pricing models. As a result, it can be a serious hassle to figure out the answer to the simple question in the title of this post. Let’s start with a pricing summary for a few of the public providers:
* See comments below for details on these
Most people are very familiar with the first item – the cost per GB in the cloud. But even this isn’t always clear cut.
When CSPs say GB, they actually mean GiB. For decades there was confusion in the computer industry as to whether a GB is 1,000,000,000 bytes or whether it’s 1,073,741,824 bytes (1024*1024*1024 bytes). This was finally resolved: Now we use GB to refer to the first (1,000,000,000 bytes) and GiB to refer to the second. (Wikipedia defines GB and GiB accurately.) So, when you’re calculating your costs, make sure you understand the correct units that you’ve measured and that your vendor is using. None of the CSPs disclose this information upfront and it took us some time to research. Typically, storage vendors like EMC, Hitachi, Seagate, IBM and others have used GB in the correct form. But for some reason, the new breed of storage in the cloud has used it incorrectly.
Now let’s look at the other charges. Many people incorrectly think these other charges are insignificant. In fact, they can be quite large. It’s also worth noting that not all CSPs have other charges.
At first blush, if you assume the same quality of product, Iron Mountain’s price of $0.65c/GiB versus Amazon’s $0.15c/GiB might seem excessive. But Amazon’s $0.15 is not all-inclusive, so there’s more to that story.
The first extra charge that some CSPs apply is the cost of transferring data into the cloud. This one is a moving target. It’s in the CSP’s interest to get data into the cloud, so often vendors will discount this charge. For instance, currently Amazon has made this charge “Free until November 1st, 2010” but then it says “Data Transfer In will be $0.100 per GB after November 1st, 2010”. To avoid the moving target, we’ll just use the stated long term pricing for Data Transfer In - even though this can change based on the various marketing drives the CSPs have at any given point in time.
The next is a Data Transfer Out charge. For the CSPs that charge this fee, none discount it from what we’ve seen. The only time you do not pay this charge is when you’re moving data around “in the network” – i.e., you’re moving data from Amazon S3 to EC2. They don’t benefit when data moves out (this doesn’t mean delete, but it means you read the data) and they need to make money on it.
Let’s say I put up some highly popular pictures of a celebrity on my S3 account and make them public. Those would be fairly small in terms of space but would have a ton of data transfer out as everyone accessed the images.
The last item is the per transaction cost. This is the cost of every operation you perform with the cloud. If you’re merely sending small quantities of files to the cloud, and rarely accessing them, this one won’t necessarily add up. A couple of our vendors, for example, charge “$0.01 per 1,000 requests” or $0.00001 per request.
But consider what would happen if I were to write 100GB of 1KiB files to the cloud. 100GiB at $0.15/GiB is a mere $15.00. That’s nothing. But how many transactions did I perform? First convert the GiB to KiB: 100GiB * 1024MiB/GiB * 1024KiB/MiB. Now divide that by the file size we wrote (1KiB). I carried out 104,857,600 transactions. That's a big number.
Now multiply that by the per transaction cost of $0.00001 and you get $1,048.58. So I paid $15 to store the data but it cost me over a thousand dollars to write it there. No, I’m not making this up. Here’s an excerpt from one of our CSP bills:
The per transaction charge is four times the storage charge. What does this mean? In short, the CSPs don’t really want small files stored in their systems.
Rackspace is a bit more explicit – they only charge you per transaction if your object size is less than 250KiB, but then their per transaction fee is higher. Why are they penalizing small files? In a word, scalability. The storage world has solved huge capacity problems over the last decade. For block storage that was the end of the story, but for file systems there’s not only the capacity problem but the scalability problem in terms of numbers of directories and files. Scalability is a very difficult problem and one that our team is very familiar with. The CSPs are telling us that this is a difficult problem and are pricing their services accordingly.
The lesson here is that it’s not just about the GBs. Total cost depends a lot on your actual usage. Let’s run some calculations.
First let’s look at Amazon and Azure with an average file size of 350KiB (the average file size of our entire user base to date), a steady data growth from 0 GiB to 1 TiB over one year and a monthly read back rate of 5% of the data set:
In month 12, Amazon and Azure’s cost per GiB would be $0.168. Nasuni would charge $0.15 per GiB. But now lets look at the same case for a 1KiB file size:
So in month 12, Amazon and Azure’s cost per GiB would be $1.04. Nasuni would charge $0.15 per GiB.
Now compare that last case to Iron Mountain:
Since Iron Mountain only charges for storage, the CSP charge is a direct passthrough and both approaches yield $0.65/GiB. So this is significantly less expensive than the $1.04 per GiB from Amazon or Azure for that use pattern.
You may be wondering how Nasuni can absorb the differences when the CSP charges are higher than what we bill our customers for the CSP portion of the bill. The answer lies in the Nasuni Filer charge. While we are charging for all the extra functionality you get with the Nasuni Filer beyond what the CSPs offer, we’re also using the Nasuni Filer charge and the law of averages within our customer base to handle the differences.
Yes, if our entire customer base started writing 1 KiB files like crazy we’d be in trouble. Fortunately there are a lot of enterprising customers writing 50 GiB files at a tremendous clip. Take this customer:
Now if you think all this has been confusing, consider that some vendors also have different pricing for different geographies. With one vendor, it costs $0.15/GiB to store data in the “US – Standard” region, but $0.165/GiB to store data in the “US – N. California” region. Nasuni does not charge differently based on the regions you choose for your CSP.
With Nasuni you can have a single bill for your cloud storage gateway and your cloud storage provider with a simple pricing model and a single company to contact when you have questions. With our recent 2.0 release you can also choose to have your own relationship with a cloud storage provider and still use the Nasuni Filer. We encourage our customers as they look at the different options to weigh the importance of features, support, and pricing against their needs and make an informed decision.
Any questions? Please let us know at feedback@nasuni.com or sound off in the comments below.