Yesterday Amazon announced their Spot pricing model. Effectively providing market driven pricing for instances on EC2. Depending on your product, this probably won’t impact you much, but it got me to thinking about pricing of the cloud. Amazon’s Web Services was a game changer when it launched. Buy the computing resources you need for only the time you needed them. However, your stuck with a very limited set of instances and therefore you need to architect your systems around their pre-defined instance sizes. While they expanded their instance offering to include high cpu and more recently high memory instances, you’re still stuck with a fairly rigid set of boxes from which to run your systems.

A specific weak spot I’m having with the pre-defined box sizes is Memcached. It turns out that Memcached is fairly light on the processor and requires essentially no disk I/O. Really the processor is just a go between for the memory and the network card. If you are looking at putting a 32Gb server online to manage the caching tier for your app, you’d need to buy the “High-Memory Double Extra Large Instance” for $1.20/hr (or $10,512/year) wait… what?! Okay, obviously we should pre-pay this, typical business model is to run the hardware over a 3 year cycle, so lets pay the $4,900 up front and then we enjoy a more comfortable $0.42/hr (or $3,679.20/year + $1,633.34/year for the pre-pay = $5,312.54 each year for 3 years). Obviously the $15,937.60 we pay over 3 years is easier to swallow than the $31,536 if we don’t pre-pay it.

Now, if your running your infrastructure in the cloud and considering using Memcached, you really can’t put a box in a rack somewhere else because the increased latency and unreliability means you may not be able to get data from your cache in a cost effective way so I’m not going to look at what buying a box with that kind of memory would cost, not to mention there is such variation in buying rack/ping/power that it would be too messy to calculate here.

This has me intruiged to see how other providers are doing their billing. I love the idea of a-la-carte servers paid by the hour. But really what would be great is allowing me to choose the CPU, memory, and I/O I need. This brings me to two smaller cloud providers who seem to have interesting offerings.

First up is 3Tera. 3Tera offers a completely different take on the cloud infrastructure model. The idea behind their offering is that you purchase hardware (or lease it) and then slice the box however you want. Basically, running your own virtual cloud! You can consider different hardware options, including stuffing a ton of RAM into weaker boxes and so on. Ultimately the product is a resource allocation tool. The dark side is that you have to pay for all that hardware, even if your not using it. Really this isn’t a cost savings over EC2. Although it’s an interesting idea if your system resource needs shift significantly over time, but are consistent enough to warrant buying or leasing hardware. I’m really interested in their technology and they have an impressive list of partners running the software that you can then lease the virtual images from.

The second provider is OpSource Cloud. OpSource charges a base fee for the VLAN service and then you build your infrastructure on top of that. The beauty is that it’s a-la-carte down to the cpu cycles and memory! Currently the memory footprint is limited to 8Gb and each machine needs between 1 and 4 CPU’s. However, this pricing model is interesting as you can provision a single CPU with 8Gb of RAM which comes out to roughly $0.24/hr (or $2,102.40/year). Starting 4 of these instances to hold the 32Gb of cache is only slightly cheaper than Amazon’s model coming in at a whopping $8,409.60/year. There are some cost savings available if you buy a silver, gold or platinum pricing tier for a monthly pre-pay. The pricing for those starts at $500/month and goes up; so you really need to have some significant hardware running to justify those costs. Another gotcha with this plan is that you need to provision a network which is $0.20/hr. I’m going to be keeping an eye on this provider. I think in the future they may have a winning solution.

Unfortunately, I don’t yet see a solution that fits my specific need. Perhaps I need to adjust my thinking and look at alternatives. It may be time to consider Amazon’s Simple DB, which provides simple key/value storage like Memcached, although as a service. Is it the answer for putting large amounts of data into a non-RDBMS? I’ll consider that in another post.

Creative Commons Photo by ArcticNomad