Can I Afford the Cloud?

Like many people I'm trying to evaluate whether I can save money by moving my lightly-loaded, community-oriented websites to Windows Azure instead of running them all on my own hardware (a web server in my garage). With the advent of the low-priced Web Sites model in Windows Azure (which I rambled on about last week), it seems like it should be a lot more attractive in financial terms than using the setup I have now.

At the moment I use a business-level ADSL connection that provides 16 fixed IP addresses and an SLA that makes the connection suitable for exposing websites and services over the Internet. With one exception the websites and services run on a single Hyper-V hosted instance of Windows Server 2008 R2, on a server that also hosts four other Hyper-V VMs. The web server VM exposes five websites; while also providing DNS services for my sites and acting as a secondary for a colleague (who provides the secondary DNS for my sites). The exception is the website running on a very old Dell workstation that displays local weather information captured from a weather monitoring station in my back garden.

In theory Windows Azure should provide a simple way to get rid of the Hyper-V hosted web server, and allow me to avoid paying the high costs of the business ADSL connection. I have a cable Internet connection that I use for my daily access to the wider world, and I could replace the ADSL connection with a simpler package at a considerably reduced cost to maintain backup and failover connectivity. I'd need to find a solution for the weather web server because it requires USB connectivity to the weather station hardware (which it why it runs on a separate server), but that's not a major issue and could be solved by posting data to a remote server over an ordinary Internet connection.

So I started evaluating possible savings. Using a separate Cloud Services Web role for each site is a non starter because the cost, together with one Windows Azure SQL Database server, is four times what I pay for the ADSL connection. Even taking into account the saving from running one less on-premises Hyper-V instance, it doesn't make sense for my situation. And I'll still need a DNS server, though I can switch to using a hosted service from another company for a few dollars per month to resolve (if you'll pardon the pun) that issue.

But I can run multiple sites in one Cloud Services Web role by using host headers, which gives me a marginal saving against the cost of the ADSL connection. Of course, according to the Windows Azure SLA I should deploy two instances of the role, which would double the cost. However, the expected downtime of a single role instance is probably less that I get using my own ADSL connection when you consider maintenance and backup for the Hyper-V role I use now.

Using a Virtual Machine seems like a sensible alternative because I can set it up as a copy of the existing server; in fact I could probably export the existing VHD as it stands and run it in Windows Azure with only minor alterations. Of course, I'd need SQL Server in the Virtual Machine as well as a DNS server, but that's all fully supported. If I could get away with running a small instance Virtual Machine, the cost is about the same as I pay for the ADSL connection. However, with only 1.75 GB of memory a small instance might struggle (the existing Hyper-V instance has 2.5 GB of memory and still struggles occasionally). A medium size instance with 3.5 GB of memory would be better, but the costs would be around double the cost of my ADSL line.

So what about the new Windows Azure Web Sites option? Disregarding the currently free shared model, I can run all five sites in one small reserved instance and use a commercial hosted DNS service. Without SQL Server installed, the 1.75 GB of memory should be fine for my needs. I also get a free shared MySQL database in that cost, but it would mean migrating the data and possibly editing the code to work with MySQL instead of SQL Server. A Windows Azure SQL Database for up to five GB of data costs around $26 per month so the difference over a year is significant, but familiarity with SQL Server and ease of maintenance and access using existing SQL Server tools would probably be an advantage.

Interestingly, Cloud Services and reserved Web Sites costs are the same when using Windows Azure SQL Database. However, the advantage of easier deployment from a range of development environments and tools would make Web Sites a more attractive option. It would also be useful for the weather website because the software I use to interface with it (Cumulus) can automatically push content to the website using FTP over any Internet connection.

So, summarizing all this I came up with the following comparisons (in US dollars excluding local taxes):

I only included one GB of outbound bandwidth because that's all I need based on average traffic volumes. However, bandwidth costs are very low so that even if I use ten times the estimated amount it adds only one dollar to the monthly costs. Also note that these costs are based on the July 2012 price list for Windows Azure services, and do not take into account current discounts on some services. For example, there is a 33% discount on the reserved Web Sites instance at the time of writing.

It looks like the last of these, one small reserved Web Sites instance with a MySQL database and externally hosted DNS is the most attractive option if I can manage with MySQL instead of Windows Azure SQL Database. However, what's interesting is that I can achieve a saving for my specific limited requirements, and that's without taking into account the hidden ancilliary costs of my on-premises setup such as maintaining and patching the O/S, licensing costs, electricity and use of space, etc.

And if the hardware in my garage fails, which I know it will some day, the cost of fixing or renewing it...