Windows Azure一般问题

Question

1. does windows azure automatically scale up(by providing more instances), or I need to change this?
2. the extra small instance costs 0.05$/hour. According to Azure SLA I need to use at least 2 instances. This means 2 * $0.05*24*30=$72/month minimum. I can get on premise asp.net hosting for $5/month. Is there any offer I don't know about so I can build from the start on Azure architecture, or should I just switch to azure when I need more scaling and other servies that Azure offers because the difference in price is too high for me.

Answer 1

1) Azure does not scale up automatically. You either need to code the feature yourself (there are plenty of open-source examples that show the basics) or use an auto-scaling service like @ http://www.paraleap.com

2) If your business is a small business (doing less then mil/year and utilizing MS technologies), you can get into Microsoft Bizspark program @ http://www.bizspark.com -- they offer 3 years of MSDN which includes 1 compute istance running at 24/7 for 16 months for free. Alternatively, if you have MSDN, you already have the 16 months of Azure for free.

Hope this helps

Answer 2

1. No you need to do this on your own by changing the configuration or do it via code where you poll the diagnostics Azure provides and increase the value of the instances. Note however that it takes like 15 minutes before the new instance is ready.

2. If you want SLA in Azure you need indeed at least 2 instances. There are several offers on Azure which already can get you kickstarted: http://www.microsoft.com/windowsazure/offers/ . But if you don't need the scaling etc and only want to run a blog/site then it's probably better to go for standard hosting at the moment. Azure has its merits and is a great environment but it's not the best environment for all circumstances. I suggest you take a look at what your application needs to do, if you foresee steep ups and downs in usage during certain hours, ...

Neudesic also created an ROI calculator for Windows Azure pricing: http://azureroi.cloudapp.net/ . But it's probably also safe to talk with a Microsoft representative in your country for exact pricings/offerings/...

Answer 3

You only need to run 2 instances if you need your service to have uptimes guaranteed by the Azure SLA.

Microsoft may occasionally need to "cycle" your instances to apply core system updates to the VMs or transfer your VMs to different hardware in the data center, etc. If you have only one instance running, your service will experience downtime of a few minutes while the update is performed. If you have two instances running, one instance will be taken offline for update while your other instance is still running and handling incoming requests. When the update on instance 1 is finished, it will be up and running handling requests while instance 2 is taken offline for update.

If you don't care about uninterrupted service uptime, you can just run 1 instance at half the price - $31 / month by your calculations.

If you're comparing against a $5/month ASP.NET hosted service, you're not comparing apples to apples. The $5/month ASP.NET hosted service almost definitely does not provide an SLA with fail-over redundancy in case of hardware failure in the data center.