Comparing Azure Website Scaling Options
I thought it would be interesting to compare the different scaling options of Azure Websites. I did this by scaling a website I had running, and looking and the allowances shown on the monitoring page of the portal.
| Scale | CPU hours/day | RAM | Dollars/month |
|---|---|---|---|
| Free + ** | 1 | 1GB | $0.00 |
| Shared (1 instance) + | 4 | 0.5GB | $9.36 |
| Shared (6 instances) + | 6 * 4 = 24? | 6 * 0.5 = 3GB? | $56.16 |
| Reserved (1 instance) | 24 | 1.75GB | $57.60 |
Did you notice that? You start paying and the available RAM goes down (1 shared instance has 0.5GB)!
When I scale to 6 instances of shared, the quotas don’t go up, but presumably the figures are then balanced across 6 machines – hence the question marks.
I also notice that 6 Shared instances is slightly cheaper than 1 Reserved, and have considerably more RAM (according to my maths). I think it’s probably better to spread your application across more shared instances, giving you better resilience.
It would be really useful is some benchmarking figures as an extra column, does anyone have any numbers?
None of these prices include the costs incurred for outbound data or storage.
+ With Free and Shared, there is also a limitation on 2.5 minutes of CPU every 5 minutes.
** With Free, there is a limitation of 165MB data out per day.
Justin are discussing. 
Richard Astbury's Blog 
Justin 3:58 pm on January 25, 2013 Permalink | Log in to Reply
How does the limitation of 2.5 minutes out of CPU utilization out of every 5 minutes work with multiple shared instances? Say you got a burst of traffic from HackerNews, would Azure be smart enough to only route to an instance with available CPU time?
Richard 4:00 pm on January 25, 2013 Permalink | Log in to Reply
Good question Justin, I have no idea how it calculates whether you’ve exceeded the metrics.