How can I estimate server costs for creating an app?

Im writing up a business plan and im having some trouble wit开发者_运维知识库h the finance part. I put an estimate on the cost of developers, web designers and everything but server costs. Im not a programmer so I dont know all the details. But how much would you think servers are going to cost for a complex app. I cant get into too many details but it keeps track of user preferences, stores data about the user and there is quite alot of back-end to it.

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As i said in my response to your comment to @mark; this is a tough question as we don't know enough to make good predictions. To help you make your own predictions

As its only a business plan (i.e. not set in stone) think of a number of users that you want to run on a given piece of hardware - for the data / web servers.

Be aggressive but in the real world as the developers will have to code to make this target and make that part of the spec for the software - 200 concurrent users on a web server for example and that 10 web servers needs a dual core xeon database server or whatever the app needs.

Then you can plot a graph of expansion as it goes; they tend not to be linear so have a lying weasel factor to handle that that rolls the graph off as you go.

Then don't forget about backup, load balancers, firewalls, content managers, caching proxies and all the other network kit you will need.

You will also need to budget for someone to run it all... If its a web app probably 3 to handle it in shifts. Either that or make sure your IT people are the most dedicated so that the servers get restarted in the night when it all goes wrong.

Finally ... Does the system need DR? if so that will need to be included.

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It really depends upon the complexity of the app, how much traffic you expect and what platform you need. The real cost is in the time managing the thing.

I would consider amazon aws (http://aws.amazon.com/ec2/pricing/). There's even a free level to get started.

They have system images prebuilt, free and purchasable, that might have the configuration you'll need. You can use one to build an image of your own and deploy it to many servers quite easily if your app takes off.

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This heavily depends on the numbers of users that concurrently use your service and of course how much traffic you will have. Without more details it is not possible to estimate any costs.

Edit:

Possibly it is the best if you sit down with a developer, explain her/him what you want to do. There is a good calculation program from amazon webservices (cloud). You can find it here: http://calculator.s3.amazonaws.com/calc5.html

For example if you would need 5 Linux CPU medium instances for one year + Load Balancers (they will spread the load to the instances) + Traffic (50000GB out + 500GB in) (per user out 1GB/month + in 100MB/month) This would be all together a One-Time payment $2275 and monthly $7101

http://calculator.s3.amazonaws.com/calc5.html?key=calc-DE0DC116-63C1-440E-BE15-213263DC4E2B

But this is a too complex question to rely only on guesses. The advantage of Amazon AWS is, that you can grow with the application. Perhaps it would be the best to start small and see what you will need.

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Take a look at the Dell, IBM or HP sites, say, and see if they quote rough figures. Compare with the cost for services like Amazon's EC2, or Microsoft's Azure. It's impossible to tell you what you need, without knowing what you're actually doing.