Steve Spencer's Blog

Blogging on Azure Stuff

Windows Azure Websites, Web API and SignalR

One of our projects involves a web service that implements both SignalR and Web API and we were looking at the quickest and most cost effective way to get it deployed so that one of our customers could run a Windows 8 application as a demo away from the office. The application works well internally as we have the service deployed on one of our servers on IIS. The options we were considering were:

  1. Package the application up in an install package, ship this to our customer and then provide them with instructions and support to allow them to deploy and configure their application
  2. Deploy it on one of our servers and then publish the service through our firewall
  3. Deploy as a Cloud service in Windows Azure
  4. Deploy as a website in Windows Azure

We considered the fact that the first option would probably take us a fair amount of time to make a deployment package, test it and provide enough documentation and support to allow our customer to deploy it on their servers. The other 3 options involved us doing a smaller amount of work, but at least we could get everything working well before shipping the demo out. Option 2 would mean using our internal resources for something that would not be used that often but we would not necessarily know whether and when it was being used so the resources would need to be kept running limiting our capacity internally. Windows Azure was a good fit for this application and the choice was really between setting up a cloud service or use a web site, I guess we could have set up a virtual machine hosted in Windows Azure, but this was a bit excessive just for a simple web service. The two remaining options were to set up a cloud service by creating a web role in deploying to Windows Azure or to use Websites. The cloud service would involve more work for us as we would need to change the project to add in the cloud service project and web role and then do a full PaaS deploy to Windows Azure. This would then utilise a whole virtual machine (although we would have used an Extra Small instance), but the web sites seem a sensible option especially as we already have a number of them available for free. How easy was this going to be and will both Web API and SignalR work with Windows Azure Websites, especially as we were using preview software. I was surprised about how easy this was to deploy and I’ll walk through the process we went through.

Step 1: Make sure that the service runs locally,

Step 2: Our service uses Code First Entity Framework using a local SQL server. Create a database using Windows Azure SQL Server via the Windows Azure Management portal (https://manage.windowsazure.com), the copy the ADO.NET connection string.

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Paste this into your web config file of the web api service. You will need to make sure that the Windows Azure SQL Server firewall has your public IP address configured and you will need to make sure that your firewall will allow connections through port 1433. Now run your application and make sure that you can connect to the Windows Azure SQL database. As we are using Code First Entity Framework, the database tables were created for me so I didn’t need to do any database deployment. The only issue I had with this approach was that I had to create the database first in Windows Azure.

Step 3: With our service running locally but with the database in Windows Azure we are now ready to deploy to the cloud. In the Windows Azure Management portal, click the “New” button

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The “Quick Create”, enter the url you want to use and click “Create Web Site”

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Step 4: We now need to deploy our service. In the Azure management portal, navigate to the web site you just created and click “Download Publishing Profile”. Save this to your computer.

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In Visual Studio 2012, open your web api project, right click on the project in Solution Explorer and click publish.

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This will display the publish dialog.

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Click the import button and navigate to the folder where the publish profile was saved. This should then allow you to complete the wizard

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Click Next and check to make sure the correct connection string is displayed, click Next then Publish. This should then start to upload your web api project to the Windows Azure Website. The deploy should be relatively quick and no where near the time it takes to deploy a cloud service. When completed, your deployed website should start in the browser and you can carry out whatever tests you need.

Step 5: With your website deployed you should just need to change the url of your service in the Window 8 application.

This whole process took less than 10 minutes to setup and deploy. One of the nice features of using websites is that changes are quick to deploy.

We had a number of issues to get this all working fully:

  1. As I mentioned earlier we had to ensure that the database was created before the EF code would create the correct tables
  2. When we first ran the Windows 8 application we were getting an error each time we tried to use SignalR. We received an “Incompatible protocol version”. This was because I installed the latest SignalR libraries on the server side code but the client was using an older version. You need to make sure that both the client and server are using the same version of SignalR
  3. We also had an issue when deployed to Windows Azure where it looked like the SignalR hubs were not being created correctly. It looked like the hub creation was hanging and not returning. This is a known issue that has been fixed but not yet deployed to Azure. There is a work around which is to configure SignalR to use long polling (https://github.com/SignalR/SignalR/issues/510). We did that with the following code:
   1: hubConnection = new HubConnection(App.SignalRUrl);            
   2: proxy = App.hubConnection.CreateHubProxy("statushub");
   3: App.hubConnection.Start(new LongPollingTransport()).Wait();

Windows Azure Web Sites is not just for web sites, using it also for services can make a lot of sense as the scaling model will allow a lot of flexibility and can provide a cost effective way to host your services, especially if they are not heavily loaded at the start. They are also easy and fast to deploy which is always a bonus Smile

Windows Azure Queues vs Service Bus Queues

If you have been wondering why you would use Windows Azure Queues that are part of the Storage Service or the queues that are part of the service bus then the following MSDN article will give you full details.

http://msdn.microsoft.com/en-us/library/hh767287(VS.103).aspx

Recent changes in pricing make the choice even harder. There are two specific areas I like that makes the service bus queue a better offering than the storage queues:

  1. Long connection timeout
  2. Topics

The long connection timeout means that I don't have to keep polling the service bus queue for messages. I can make a connection for say 20 minutes and then when a message is added to the queue my application immediately returns the data, which you then process and then reconnect to the queue to get the next message. After 20 minutes without a message the connection closes in the same way it does when a message is received except that the message is null. You then just reconnect again for another 20 minute. The makes your application a more event driven application rather than a polling application and it should be more responsive. You can make multiple connections to the queue this way and load balance in the same way as you would when polling queues.

The following code shows how you can connect with a long poll.

 1: NamespaceManager namespaceManager;
 2: MessagingFactory messagingFactory;
 3: Uri namespaceAddress = ServiceBusEnvironment.CreateServiceUri("sb", "yournamespace", string.Empty);
 4:  
 5: namespaceManager = new NamespaceManager(namespaceAddress, TokenProvider.CreateSharedSecretTokenProvider("yourIssuerName", "yourIssuerKey"));
 6: messagingFactory = MessagingFactory.Create(namespaceAddress, TokenProvider.CreateSharedSecretTokenProvider("yourIssuerName", "yourIssuerKey"));
 7:  
 8: WaitTimeInMinutes = 20;
 9:  
 10: // check to see if the queue exists. If not then create it
 11: if (!namespaceManager.QueueExists(queueName))
 12: {
 13:     namespaceManager.CreateQueue(queueName);
 14: }
 15:  
 16: QueueClient queueClient = messagingFactory.CreateQueueClient(queueName, ReceiveMode.PeekLock);
 17:  
 18: queueClient.BeginReceive(new TimeSpan(0, WaitTimeInMinutes, 0), this.ReceiveCompleted, messageCount);

When a message is received or the 20 minute timeout expires then the ReceiveCompleted delegate is called and a check is made to see if the message is not null before processing it.Once processed another long poll connecting is made and the process repeats. The beauty of this method is that you don’t have to manage timers or separate threads manage the queue.

Topics are private queues that are subscribed to by consumers and each private queue will receive a copy of the messages put into the original queue and are all manages individually. Topics can also apply filters to the message so that they only receive messages that they are interested in.

Further details of Service bus topics and queues

http://www.windowsazure.com/en-us/develop/net/how-to-guides/service-bus-topics/

Windows Azure Training Kit–June 2012 Release

The Windows Azure Training Kit June 2012 release is out now with the following features:

  • 12 new hands-on labs for Windows Azure Virtual Machines
  • 11 new hands-on labs for Windows Azure Web Sites
  • 2 new hands-on labs demonstrating Windows Azure with Windows 8 Metro-style applications
  • Several new hands-on labs for Node.js and PHP using Mac OS X
  • Updated content for the latest Windows Azure SDKs, tools, and new Windows Azure Management Portal
  • New and updated presentations designed to support individual sessions to a full 3 day training workshops

Publishing Windows Azure Websites with TFS

This is a follow on post from my introduction to Windows Azure Websites and shows you how you can synchronise your website in TFS with Windows Azure.

One of the biggest problems with the way you deploy applications to  Windows Azure is that minor changes (e.g .markup, content and styling) require a redeploy to publish the changes. Windows Azure Websites solves this problem by allowing you to synchronise your website with Team Foundation Server or GIT.

In this post I will show you how easy it is to manage your websites in version controlled environment using Team Foundation Service. Team Foundation Service is a cloud hosted version of Team Foundation Server.

This works by creating a continuous integration build with your source code that will automatically deploy your website after successful build each time code is checked in.

This is configured as follows:

Click the “+” button at the bottom of your portal screen and select Website –> Quick Create

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Enter the url details and click Create Web Site

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An Empty site has now been created.

This site now needs to be link to your Team Foundation Service. Click on the website in the dash board and then select “Setup TFS Publishing”. you will also note that you can use a GIT repository as well as TFS.

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Enter your TFS url (or create a new one), then click Authorize Now.

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this connects through to your TFS service and setup the CI build that will deploy your application to the cloud.

The TFS site will now be displayed asking you to authorize the connection

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You now need to pick the website you want to deploy. If you haven’t create a site yet then you need to go to ~Visual Studio, create your site and check it in to TFS.

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You have now linked your web site in TFS to the Azure Website. This will take a few moments to synchronise.

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Your website has not been deployed yet. You need to make a change and then check the changes in

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upon check-in the build is started

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When the build is complete the new website is deployed

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You can also revert back to older versions of the web site by clicking the desired version and then clicking redeploy:

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This will start the redeploy of the older version:

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A new build is kicked off using the same changeset details as the original deployment. Once the build is complete the  web site is reverted back. this whole cycle only took a few minutes so it is a lot faster than the redeploy mechanism you had previously.

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TFS and Windows Azure provide a good mechanism for version controlling your website. Adding application life cycle management to any software development activity is a good thing.

Introducing Windows Azure Websites

After the announcement about the new Windows Azure Services to Deliver a Hybrid Cloud and on Scott Guthrie’s blog, this blog post shows a little of what the Windows Azure Websites will bring.

These are additional services that allow quick and easy creation and deployment of websites to the Windows Azure environment. Websites can be deployed using templates from some of the leading CMS/Blog providers (e.g. Word Press, Umbraco, Orchard, DotNetNuke) as well as being able to deploy your own websites. Windows Azure websites supports a number of technologies (e.g. ASP.NET, PHP, Node.js and Classic ASP). Upon deploying a website to Windows Azure you will have all the benefits of the Windows Azure cloud computing platform for scalability, resilience and performance. This post will guide you through setting up a new CMS enabled website using one of the templates.

When logging in, the first thing to note is the new portal. This is a rewrite in HTML5.

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Click on “Websites” in the left hand column:

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The click “Create a website”:

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Click “From Gallery”, enter your url and click “Create Web Site”

You can now choose from a number of templates

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Pick the template you want and press Next

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Enter the details on the form (don't for get to scroll down to enter your password)

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click Next to specify your database settings

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and Next again to specify your database server settings

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Clicking Next will now provision your new Umbraco website

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Clicking on the bar graph on the bottom right corner give you a status update.

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The whole deployment took about 3 minutes. Your website is now ready to use. Although you will need to now add in the content and configure up Umbraco. Navigating to your new website will guide you through the install process.

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In order to configure Umbraco you will need your database connection string. this can be found back in the Portal:

Click on the SQL Databases tab

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Click the database name the View Connection String

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You can now get the server and database names

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Now you can finish installing Umbraco. when complete you will need to add your own content

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This whole process is fast and easy and will allow you to deploy websites for your customers in a fast and efficient way. Now it is running one final  and useful feature that has been added to the portal is a dashboard where you can se the health of your website as well as  being able to scale the website if required

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Look out for a follow on post that shows you how to synchronise your website in the cloud with Team Foundation Service.

Windows Azure Diagnostics

Diagnostics in any application is a necessity and Windows Azure applications are no different. You could remote desktop onto the instance and check the event logs and even run up debug view so that you can see your system diagnostic messages. There is however a mechanism provided to retrieve a whole load of diagnostic information. By enabling Windows Azure Diagnostics you can retrieve the diagnostic trace logs, windows event logs, performance counters and other useful data. Enabling Windows Azure Diagnostics can be done by setting the Enable Diagnostics check in the configuration of each Azure role. You also need to add a diagnostic connection string as follows:

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This enables diagnostics but this alone will not provide you with any information. Windows Azure diagnostics works by capturing the data that you have requested and periodically transferring it to table or blob storage where you can view the information. The information can be requested by configuring the diagnostics you require either in code or in a config file. The config file resides in blob storage and can be changed at runtime so it make sense to use that configuration mechanism rather than code as it can be easily turned off when not in use.

Firstly you may want to retrieve your tracing information that is traced using System.Diagnostic.Trace. the easiest way to do this is to add a trace listener. The Windows Azure SDK contains one that can be used. this is called DiagnosticMonitorTraceListener. This can be added to the web.config file in the same way as other listeners or via code. When I added it to the web config file I had issue on certain projects where the Windows Azure Diagnostics assembly could not be found. Adding the configuration in code always seemed to work. As you will need to redeploy anyway to update your web config file in Windows Azure it makes little difference whether the configuration is in code or the web config file (except that you need to rebuild). In order to add it to code I added the following line to the  global.asx.cs file:

   1: void Application_Start(object sender, EventArgs e)
   2: {
   3:     // Code that runs on application startup
   4:     System.Diagnostics.Trace.Listeners.Add(new Microsoft.WindowsAzure.Diagnostics.DiagnosticMonitorTraceListener());
   5: }

You now need to modify the config file located in blob storage. The config file is located in blob storage inside the wad-control-container. There will be a config file in here for each deployment you have made with diagnostics enabled and for each instance. You will need to update each instance you wish to receive diagnostic information from.

Tracing can be enabled by modifying the following xml accordingly:

   1: <Logs>
   2:   <BufferQuotaInMB>1024</BufferQuotaInMB>
   3:   <ScheduledTransferPeriodInMinutes>5</ScheduledTransferPeriodInMinutes>
   4:   <ScheduledTransferLogLevelFilter>Verbose</ScheduledTransferLogLevelFilter>
   5: </Logs>

This will transfer the logs at 5 minute intervals at the highest log level. You can change the level to be Information or Error which represents whether you have used TraceInformation or TraceError whereas Verbose traces both and using Trace.WriteLine. The logs will be transferred to table storage in a table called “WADLogs”

Performance counters can be configured as follows:

   1: <PerformanceCounters>
   2:   <BufferQuotaInMB>0</BufferQuotaInMB>
   3:   <ScheduledTransferPeriodInMinutes>5</ScheduledTransferPeriodInMinutes>
   4:   <Subscriptions>
   5:     <PerformanceCounterConfiguration>
   6:       <CounterSpecifier>\Processor(_Total)\% Processor Time</CounterSpecifier>
   7:       <SampleRateInSeconds>30</SampleRateInSeconds>
   8:     </PerformanceCounterConfiguration>
   9:     <PerformanceCounterConfiguration>
  10:       <CounterSpecifier>\Memory\Available Bytes</CounterSpecifier>
  11:       <SampleRateInSeconds>30</SampleRateInSeconds>
  12:     </PerformanceCounterConfiguration>
  13:   </Subscriptions>
  14: </PerformanceCounters>

This will transfer the processor percentage and available bytes every 5 minutes with a 30 second sampling frequency. These are stored in table storage in a table called “WADPerformanceCountersTable”. Information about the performance counters that are available can be found here:

Event logs can be configured as follows:

   1: <WindowsEventLog bufferQuotaInMB="0"
   2:      scheduledTransferLogLevelFilter="Verbose"
   3:      scheduledTransferPeriod="1">
   4: <!-- The event log name is in the same format as the imperative 
   5:        diagnostics configuration API -->
   6:     <DataSource name="Application!*" />
   7:     <DataSource name="System!*" />
   8: </WindowsEventLog>

These are stored in a table called “WADWindowsEventLogsTable”.

Further information can be found at:

Example configuration file

Overview of Storing and Viewing Diagnostic Data in Windows Azure Storage

Imagine Cup NE

Just finished at the Hacking Imagination event in County Durham. My role was to help mentor and encourage the students from Universities and Colleges in the North East of England to help them to develop their ideas for their Imagine Cup entries.

The event was held in a secret location in county Durham and the students were bussed in.

DSC_0163

A number of us from Black Marble attended and performed workshops in Migrating to Azure (me), ALM/TFS (Richard), WPF, SilverLight, Phone 7 101 (Leon), Planning Poker (Me, Leon) & Software War Stories/How to Run a Software Business(Robert, Me). The students were all enthusiastic and asked a lot of sensible questions. The students were put into teams if they hadn’t already formed them, which was interesting to watch as an outsider as it was a bit like a recruitment fair with students walking around from team to team where both sides were deciding whether the person or the team were a good fit. This seemed to have worked well with everyone having a team. the age and skill levels range from college students doing their A levels to MSc.

The aim of the two days was to get the teams in a position where they had an idea that is more than just a software app with a good justification for it. This was a difficult task for a lot of teams as they either had a technology solution and tried to find a problem to solve or a really wide problem that they were trying to solve. Most of the discussions were around getting the teams to think about the whole solution including who it is aimed at and how they are going to deliver it rather than just the software side of the solution. It was also about getting some of the teams to focus down on to a specific area rather than being general. Some of the ideas changed each time I spoke to the teams!!

The (long) 2 days ended with each of the teams doing a presentation of their ideas to the whole group. The whole 2 days was enjoyable and the students seemed to gain a lot from the experiences, bringing some out of their shells.

The thing that impressed me most was the amount of young talent that is around and the abilities they have. One group of students were from a 6th form college doing their A Levels/BTEC and the college had around 15 – 20 attendees, all working hard to deliver a good thought through ideas and presenting their ideas to a group of about 50 people. That is something I used to avoid as much as possible when I was at that age. It is this talent that is the future of IT. Credit must go to the teacher/lecturer who has encouraged this amount of A Level/BTEC students to attend an event like this. Its not an easy task to get teenagers to do anything (he says from experience).

Events like the Imagine cup helps these guys (and girls) to gain real world experience and advice from experts in the field. Getting a chance to influence and help this talent has been rewarding for me and I want to try to help some of these young people more. So thanks to all the people who organised and mentored the event and thanks to the students that attended.

There was a lot of information being passed around and to finish off this post, I’ve put together a list of some of the areas that we were talking about in my sessions. I hope they are useful.

Video of wiring the Windows Azure Access Control service into an ASP.NET website. My bit is at the end and its a no code demo to allow users to login to you website using Live, Google or Yahoo accounts.

The Windows Azure Platform training Kit

The Windows Identity training Kit

Windows Azure Pricing& MSDN subscription allowances

Team Foundation Server in the Cloud

Books

Don't Make Me Think!: A Common Sense Approach to Web Usability : Steve Krug (ISBN: 0321344758)

The Art of Unit Testing – Roy Oshrove

Windows Azure Boot Camp – SQL Azure links

I promised a number of links during the SQL Azure talk at the London Windows Azure boot camp today & here they are:

Migration wizard
http://sqlazuremw.codeplex.com/

SQL Azure Federations
http://msdn.microsoft.com/en-us/library/windowsazure/hh597452.aspx

Unsupported SQL Azure T-SQL

http://msdn.microsoft.com/en-us/library/windowsazure/ee336253.aspx

Partially Supported T-SQL
http://msdn.microsoft.com/en-us/library/windowsazure/ee336267.aspx

Azure Costing Considerations

Costing a system for running on Windows Azure seems complex at times and sometimes it is easy to calculate and other times it is not. However there have been a number of times in recent months where I have experienced higher than expected costs for Windows Azure. The first thing to check is the actual bill. The bills are pretty comprehensive and will itemise the usage pretty well. You should easily be able to identify overspend. The following areas are where we have seen unexpected expenses appear.

Compute

The compute prices are straight forward in Windows Azure and you pay for each instance hour you use. The minimum duration is 1 hour and is metered in blocks of hours that means if you have an instance running for 1 minute or 59 minutes you will be charged for 1 hour, similarly if you had 2 instances running at the start of the hour and then turn one off you would still be charged for 2 hours. It may also get complicated if you then put the second instance back up within the same hour. You will probably be charged for 3 hours as the second instance reappearing would be treated as a new deployment and would most likely be on a different machine (although I’ve never checked this) thus being seen as different to the first time the instance was active at the beginning of the hour. This in reality won’t cost you too much as these examples are not likely to happen. What is likely to happen and could cost a significant amount are the following

· Staging & Production

· Instance count

When you upgrade your system using the VIP swap mechanism, you will deploy your new software to the Staging area, do your testing and then VIP swap Production for Staging. During the period where you have something deployed in Staging you will be charged for the number of instances you have running in Production plus the number of instances you have running in Staging. For example I have deployed 2 instances to Production and want to upgrade my software using VIP swap. I then deploy my software to Staging configured to have 2 instances running and carry out the tests. This process takes 30 minutes. I then VIP swap Staging to Production. I will be charged for 4 instances for that hour. If I then do not undeploy the software that is currently in Staging (i.e. the old software that was previously in Production) I will continue to be charged for 4 instances. You may want to leave the old software there so that you can swap back easily if there is an issue, but remember you are being charged twice still.

Another area where you could be getting billed is if you don’t bring the instance count back down after your peak loading has subsided. An example of this is that you increase your instance count on your website just before a big marketing campaign kicks in. Once the campaign is complete it is likely that the load of your website will drop. At this point it would make sense to reduce the instance count of your website otherwise you are paying more that you need to for your site.

Data

With Windows Azure storage you get charged for the space needed to store the data, the cost to transfer the data out of the data centre and the cost of transactions on the data storage API. Just to clarify a storage transaction is effectively a call to the Storage API, whether that is to retrieve data, query queues, delete data etc. Each is at least one transaction (Some data retrievals might be multiple SDK calls). Data storage costs are straightforward, but bandwidth and transaction costs could take you by surprise if you are not careful.

Bandwidth charges cover the cost to extract data from the data centre, that could be the presentation of a web page to a user, extraction of a blob extracting data from a queue outside of Windows Azure etc. unless you are regularly moving data outside of Windows azure the bandwidth costs are relatively small (when compared to the compute costs) e.g. $0.12 per GB. Another thing to bear in mind is that data transfer within the data centre is free and also data transferred into the data centre is also currently free. This means you can put a lot of data into a data centre, process it and then store it without incurring any bandwidth charges. You will only be charged for bandwidth when you pull the data out of the data centre. It is therefore important to make sure that if you are transferring data around your system that all your compute and data storage (Storage and SQL Azure) are all in the same data centre. If you don’t then you will be charged for bandwidth to get the data from one data centre to another. For example, in the diagram below we put our web site in Dublin and SQL Azure in Amsterdam.

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In the simple scenario of putting some data into our database from a website and then doing a single retrieve you can see that the data will incur 3 bandwidth charges when it should only have 1. With a lot of data transfers the costs will soon mount up.

Transactions charges also appear to be relatively low when compared to compute costs and most of the time they are, but as you are charged each time a method on the Storage API is called you could be getting charged even when there is no data being processed. This would happen when you are processing a queue. Each time you call the SDK to see if there is something to process you would be registering a transaction, therefore if you had this code in a loop that regularly checked the queue you could start to rack up hidden costs. For example a queue is polled once per second this would cost around $300 per year, however if you then reduced the polling time to check it every 100ms then the cost would be around $3000 per year, now multiply that by the number of instance you have running and the costs significantly rise. Do you really need to poll every 100ms, can you redesign to an event driven system or poll less often. Polling the queue every minute for example reduces the costs from $3000 to $5 per year

The charging concept needs to be understood by your developers so that they you don’t end up with surprise bills. You also need to be careful not to engineer a solution that is overly complex just to save transaction costs when the costs could be negligible in the scheme of things. Sensible calculations up front can help you to balance the costs effectively but watch out for the charges mentioned above as these are often done by mistake.