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On Windows Azure Portal ( as of Jan 2013) What do i get when i scale the Windows Azure Website instance from 1 to 6? Does it mean there will be 6 physical instances of my website on the same server? In IIS terms are there 6 running websites all automatically load balanced?

But judging from the help text it refers to instances as processes? If so, my website will get 6 CPUs, RAM or what?

Windows Azure Portal

Cheers

atp03
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  • belongs to serverfault.com . 6 instances = 6 parallel running sites. Visitors won't notice the difference, but performance is 6x when you use 6 instances. – Raptor Jan 02 '13 at 07:22
  • @ShivanRaptor So in IIS terms it means 6 physical websites (on the same server?) all automatically load balanced? – atp03 Jan 02 '13 at 07:23
  • Yes / No, as load balancing's concept is to separate 6 physical machines; in Azure, they are not. They just allocate more resources to you. – Raptor Jan 02 '13 at 07:29
  • @ShivanRaptor thanks for the prompt reply. Your 2nd message contradicts your first message. So 6 instances means i get 6 times the resources? As per my original question - I'm not exactly sure what i'm getting for my 6 instances. – atp03 Jan 02 '13 at 07:32
  • yes, 6 times of resources. If you encounter performance issues, you should increase instance count. – Raptor Jan 02 '13 at 07:34
  • if it is for the performance, also consider making it RESERVED instance and pick the size [SMALL, MEDIUM & LARGE] for dedicated performance. SHARED and FREE mode are served from common pool. – Naveen Vijay Jan 02 '13 at 08:46
  • @ShivanRaptor Thanks do you know any official links which confirms this? Just want to make sure :p – atp03 Jan 02 '13 at 08:47
  • 6 instances also mean that the cost will be 6x(cost * 6) – Behroz Sikander Jan 02 '13 at 09:25
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    Why the close? Why have the Azure tags if we can't ask these kind of questions? At least migrate the question....? – atp03 Jan 02 '13 at 09:58
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    I agree that I do not understand the need to close this as off-topic, this is very relevant for web development. with the cloud the lines between operations and development are blurred by definition and too many questions (including some of mine) have been closed as off-topic or moved to server fault for no good reason. – Yossi Dahan Jan 02 '13 at 13:42

1 Answers1

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Windows Azure Websites, unlike Windows Azure Web Roles, is a 'high-density' multi-tenancy platform which does not use virtual machines as a scale unit but processes.

When you use Web Roles (or Worker Roles, or Virtual Machines for that matter) every instance equals a virtual machine whose 'specs' are determined by the instance size selected.

When you use WebSites you can chose between a shared instance and a reserved instance:

Reserved instances are pretty much like web roles from a scale point of view so the scale unit is of a virtual machine (and you pay accordingly)

Shared instances use the high-density model in which multiple tenant may exist on the same virtual machine but each has it's own process with isolation being provided by the platform through sandboxing.

In the shared instance case the scale unit is not an entire machine but rather an additional process, which is very likely to run on a separate virtual machine.

Yossi Dahan
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  • Are Shared Mode instances considered to be a HA/Load Balanced solution as well? – atp03 Jan 02 '13 at 09:53
  • They are load balanced and the platform will recover from failures at the level it manages (i.e. outside your code) automatically. whether that's a complete-enough HA solution is your call. – Yossi Dahan Jan 02 '13 at 10:02