Ever since the Google App Engine was released, I’ve been fascinated with cloud computing frameworks. The vision is to have a website that can scale from nothing to infinity, without having to worry about servers, viruses, uptime, etc. I’ve finally gotten a chance to play around with Azure, and I must say that I’m in love with the concept, but disappointed by the current reality.

Performance

I’ve taken a site that I consider a “playground site”, and converted it over to run in Azure. One of the metrics I wanted to look at was the responsiveness of the deployed application. I run the main version of the site on a dedicated server, and I don’t think it’s unreasonable to use that as a baseline. After all, the purpose of Azure is to have the advantages of all the different types of hosting, yet have less to worry about.

To gauge performance, I used the Firefox add-in called Firebug. This let me see the amount of time that each requested element took to be transferred from the server. It also gives some insight into the amount of time it takes for the page to render. In the future, I’m going to use some server tracing to find specific operations that may be taking longer.

This is the baseline data from http://www.simpletracking.com. As you can see, the page is served up very quickly. The page takes less than 100ms to render (1/10 of a second), and the entire page comes through in less than half of a second.

Now take a look at the same code running on Azure:

To render the page, instead of 89ms, it now takes ~650ms. It takes a full second for the entire page and its elements to be sent down to the client.

Running both pages several times started to give me interesting results. The dedicated server was giving me extremely consistent results (even with other users hitting it). Azure however, was all across the board. It was typically around 1 second for the entire page to render, but would spike up to 5 seconds occasionally. Personally, I think this is completely unacceptable performance. Hopefully this is not indicative of the performance I can expect once it’s released.

IoC

Azure is designed so that if you have an application that runs in medium trust, it shouldn’t require any conversion to run straight in Azure (in most cases). If you’re using a database, there are other restrictions because Azure doesn’t use a standard SQL database. In addition to these obvious issues, a non-obvious issue is that if you’re using an IoC container, it probably won’t run in medium trust.

My application uses the IoC container Spring.NET, which immediately failed. I suspected (incorrectly) that Windsor might have worked better, but couldn’t tell from the documentation. To make it easy to plug in different IoC containers, I started using the Common Service Locator. If you’re doing IoC without the common service locator, I really recommend you check it out.

I was then fortunate enough to find this page, which has great information on the different IoC containers and their Azure compatibility:

Castle Windsor - My preferred IoC container, but it won’t run under medium trust. Out!

StructureMap - My second favorite IoC container. Runs under medium trust locally, but not under Azure. Submitted bug report to Jeremy Miller. Reading through the StructureMap user’s group, it looks like he’s going to try to fix that early this year.

Ninject - I didn’t really monkey around with Ninject much. The sample code I saw was riddled with [Inject] attributes, which kinda turned me off. Apologies to @nkohari if I dismissed it too early.

Autofac - Works great in medium trust under Azure, easy to configure, but doesn’t support registering arguments for constructor injection at configuration time. You have to specify them when you resolve the service.

Unity - No problems at all! Worked great in medium trust on Azure, easy to configure, supports everything I need! I gotta say I’m really impressed by how far Unity has come in such a short time.

My only reasonable option was Unity, which is Microsoft’s IoC container. After another fun conversion, I was up and running! I honestly don’t have any complaints about their IoC offering.

Instances

The Azure team decided to introduce the concept of “Instances”. You have to decide how many virtual instances of a web server that you want running. I really don’t understand the logic here. Their sales pitch is all about handing unpredictable traffic patterns, yet an instance based approach just gives me another aspect of the application that I have to worry about. They’re promising that a configurable heuristics system will eventually be in place to handle the management of the number of instances. In effect, they are putting a band aid on a problem that they’ve created even before release.

Contrast this design with the Google App Engine. With their system, you don’t have to worry about configuring instances at all. It automagically scales from nothing to infinity automatically.

Instances on the worker roles make sense. Worker roles are not public facing, they are there to process data. By configuring the number of worker role instances, I can change the rate at which my data gets processed.

Conclusion

I realize that Azure isn’t even in beta yet, so I shouldn’t expect the world. I had my fingers crossed that their CTP would be production quality (wouldn’t that be nice?). I think that Microsoft will eventually have a great cloud platform on their hands, it’s simply a question of timing. Personally, I really don’t want to have to worry about uptime, scaling, RAID, drivers, viruses, etc. so I think cloud computing is the inevitable solution.

A couple of weeks ago, I finally signed up for DropBox. If you’re unfamiliar with the service, it’s a file synchronization service. You install a client on multiple machines, and you get a special folder (aka a dropbox). When you make changes on any computer, it’s synchronized with a central server, as well as the other clients.

Now that I’ve gotten the chance to put DropBox through its paces, I have to say that I’m very impressed. I’ve done a lot of operations that can sometimes choke file monitoring software like moving and renaming files, copying files while synchronizing, and in-use files. DropBox powered through like a champ, never giving me any errors, and without any noticeable mistakes.

In addition to simply synchronizing your files, their service also keeps a copy of your files on their server. Better yet, it automatically revisions the files. It seems to be fairly efficient, even considering all my files and revisions. Right now I’m only using 7.8% of the 2GB of space they give you for free.

One of the applications that I use the most is OneNote. Pretty much all of my disconnected thoughts go into OneNote until I can get them organized. I figured it was a great application to test the responsiveness of DropBox. I opened OneNote on two different computers. When I changed the text on one machine, the changes showed up on the other in 10-15 seconds. Perfect for keeping my notes in sync!

My one and only complaint about DropBox is that I can’t create multiple DropBoxes. A single DropBox is simple and efficient, but it would be nice to have a little more flexibility.

Live Mesh

A few nights ago, I got a demo of the Azure platform by a Microsoft Evangelist. Azure is a huge blank term for a group of confusing technologies. Even the name itself is confusing, since Azure is a cloud computing platform and is also the color of the sky when there are no clouds.

More importantly, one great thing to come out of the “Live Services” portion, is a free product called “Live Mesh”. It’s essentially a competitor to DropBox. The nice thing about Live Mesh is it’s flexibility. I can make any number of synchronized folders, and they all seem to be as reliable as DropBox. Thanks to a sophisticated permissions system, you can even share folders with other people. For example, you can have a folder set up to distribute your photos to your family.

The Microsoft Azure Evangelist showed us a demo with the client installed on his laptop, and another client installed on his Windows Mobile phone. When he takes a picture on his phone, it’s immediately pushed over to the other clients. It’s a neat trick, and does make my mobile device more useful.

As far as I can tell, Live Mesh doesn’t have plans to support a revision system like DropBox. I think this is a horrible, horrible mistake. Having a file on multiple machines provides nice redundancy, yet if you accidentally delete a file on one computer, Live Mesh will happily delete every copy of it. It even happened to Scott Hanselman. In my opinion, this completely destroys any hope it has of competing with DropBox (at least for me). I’m hoping that they’ll add a backup feature, or someone will use their API to add it for them.

Others

One service I have yet to try is SugarSync. It looks promising because it syncs multiple folders, stores revisions, and even has a Windows Mobile version (although it’s missing real-time sync). On paper, it looks like it has all the options you would expect from this type of service.

Syncplicity looks respectable, but with so many alternatives, I’m just not sure if they have anything unique that sets them apart.

Conclusion

I think this type of application is going to have a huge market. This is one of those few killer app’s that if done well, will be on everyone’s computer. Obviously Microsoft’s offering will be positioned to dominate, but we all know that they don’t always have the absolute best product.

For now, I’ll be using DropBox for my main document folder. It suits my needs, and until it messes up, I won’t need to look elsewhere.

I recently spent nearly an hour trying to figure out why all of my unit tests stopped working in a particular class. It turns out that I had accidentally deleted a single character in one of my strings, but the built in diff tool that comes with Team Foundation Server is very simplistic. Learn how and why you can replace your stock compare tool with something a little more powerful.

Here is a screenshot of what you’ll see in the stock Team Foundation Server compare tool:

See how hard it is to spot the difference? The problem is, ANY change on the entire line causes it to show up as “changed”. That includes whitespace changes. For this reason, I frequently end up with extra full lines that are colored as having been changed, making it harder to see the actual code changes. For the most part, I really don’t care about whitespace changes because they deal with the formatting of the document, and I’m more concerned with functional changes to my code.

The good news is that those smart guys at Microsoft make it easy to integrate a third party compare tool right into their tools. James Manning was even kind enough to include detailed instructions and the exact settings needed for every major compare tool. You can even use them for merging if you like.

Since my background is in Subversion and TortoiseSVN specifically, I pulled out my trusty KDiff3 (SourceForge) compare tool. It’s a common alternative for TortoiseSVN’s own diff tool.

After wiring up KDiff3, here is what I saw when I compared revisions:

Notice how easy it is to see that I changed a single letter (it’s obviously easier when it’s full-size).

There are other good reasons to use a third party compare tool (which vary by tool obviously):

• Easily compare entire file structures (folder diff)
• Inline editing
• Easy to use outside of Visual Studio - often with an explorer context menu

I recommend giving a few of the compare tools a try and see which works best for you. I don’t really see any risk in using a third party compare tool, but there are certainly a lot of advantages that you may not even know you’re missing right now. I suggest also taking a look at WinMerge in addition to KDiff3, since it seems to be fairly popular and feature-rich as well.

A new feature in XP SP3 that should of particular interest to developers is ClearType over RDP (remote desktop protocol). If you occasionally use remote desktop to work from home, or work remotely to your development machine, please read on.

If you’re not familiar with ClearType, you can head over to Wikipedia for a full explanation. In a nutshell, it takes advantage of the fact that each pixel in an LCD screen actually has 3 sub-pixels. They can be “hacked” to improve the anti-aliasing of text displayed on the screen. I’ve been a huge fan of the feature, especially for source code, and I have a hard time living without it. In XP (locally), it’s turned off by default, but turned on in Vista.

I had always noticed the remote desktop would not give me ClearType. However, I became curious when I found the following options on my Vista machine. Apparently ClearType over RDP is now supported in the client, and is also supported when using Vista as the RDP server (no hacking needed).

Unfortunately, these options have no effect when using XP. If you want ClearType over RDP with XP SP3 (sorry, only SP3+), add the following registry key:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations]
"AllowFontAntiAlias"=dword:00000001

After you add that registry key, simply reboot the server (XP), and reconnect. From what I can tell, the client options no longer matter. Even if I uncheck the “Font Smoothing” option, it still uses ClearType. It’s not a big deal, but I thought it was worth mentioning.

So far, after using this option for a while, I haven’t seen a significant performance impact over a VPN on the Internet.

If you want to take this a step further, install Consolas, it’s a font designed specifically for software development, and to take advantage of ClearType. It’s a free download from Microsoft.

Everyone seems to be getting excited lately about the prospect of cloud computing. Just like many others, I get excited by the idea that I wouldn’t have to worry about adding servers to scale up. Theoretically, a guy (or girl) could make the next YouTube, in his basement, for free. However, there is one huge advantage that most people ignore, and that’s the fact that’s also perfect for a small scale website.

I’ve tried or considered many different ways of hosting my content:

• Shared hosting - Cheaply host your sites, but be at the mercy of their IT guy messing with your computer and rebooting it for automatic updates. Also, in my experience, the performance is terrible if your traffic spikes. They typically have hundreds of users on the same server as you, and you all get to compete for performance.
• Dedicated hosting - This is what I use now, because it ensures that I get the full performance of a machine. The disadvantage is that I have a single point of failure, and I have to manage the machine myself.
• Hosting from home - Yes, people actually do this. If you have a high enough upload speed it shouldn’t be too bad. The problem is that your connection typically won’t be able to handle traffic spikes. You’ll also potentially be a victim of power or Internet outages, where professional hosts would have redundant systems in place (in theory).

Now, let’s talk about cloud computing. That magical cloud that many don’t understand. There are two potentially viable cloud computing methods available right now:

• Cloud virtual machines - Amazon’s EC2 solution is probably the most popular in this category. Basically, you can create, start, and stop virtual machines remotely. You just pay an hourly rate while the computer is running. You can even upgrade and downgrade the hardware as needed. The advantage is that you can treat the computer like a physical machine and configure and use it however you like. The disadvantage is that maintaining individual machines can be time consuming and is not necessarily part of your core business.
• Cloud application server - Instead of creating virtual machines, a cloud application server runs your application directly. You no longer worry about the constraints of a physical machine. You application could potentially be run on dozens or hundreds of servers simultaneously. The major advantage is that there is little to no maintenance, because that is the job of the provider.

I see the cloud application server as having some of the greatest advantages. You’re free to write your application with a level of abstraction, which allows you to solve the problems you really want to solve.

One of the most well known cloud application services is the Google App Engine, which currently supports Python applications. Microsoft joined the game recently with Azure for ASP.NET.

As I mentioned, not only do application servers let your applications scale up, they let you pay only for what you use. This is great for the small to medium website’s that are stuck with bad shared hosting or difficult-to-manage dedicated hosting. The fact is that most sites get a few hundred visitors daily or less. If you start to think about how often a page is actually requested, you’ll realize that it’s not very much. Even with 500 users requesting 5 pages each in a 12 hour period can easily be handled with a very low end server from years ago.

The reason that application servers are so much more efficient than shared hosting is because they’re built from the ground up to spread the load around. This results in higher utilization, but more headroom for any single application. Shared hosting providers can move users between servers, but it’s usually a manual, and often difficult process. You’re bound to a specific physical machine (unless it’s VPS hosting), and if it goes down, so does your site.

Cloud computing is also a great way to handle traffic spikes such as the Digg effect. Let’s say that you only have 500 visitors today, but might get 10, 100, or 1000 times more in a single day. It happened to FaceStat. They went from 10,000 page views per day to almost a million because of a story on the front page of Yahoo. They had to scramble to add application servers and develop a scaling strategy immediately.

Conclusion - Cloud Application Server Benefits

Cloud computing has tremendous benefits. You no longer have to worry about scaling the underlying hardware, you simply pay as you go, and you can handle traffic spikes with ease. Once cloud computing becomes mainstream and absolutely reliable, there will be few reasons to not use it.