#SEQ keyword in Asp.Net Charting control with multiple Azure Cloud app instances

Question

I am having a simple Azure cloud app(WebRole=ASP.Net MVC) which draws charts using ASP.Net Charting control.

Specifications-->

1. Chart RenderType = ImageMap
2. Chart ImageLocation = "/Images/Chart_#SEQ(1000,1)"
3. Number of app instances deployed on Windows Azure = 5
4. App contains a button which draws charts as per users parameters. When user clicks on this button, MVC action is called which provides necessary ViewData for drawing chart and returns a partial view which after getting rendered sends ImageMap and Image location to client.

When I try to draw charts from IE8 I always get the charts as per my parameters but when I simulataneously try to draw charts on FireFox sometimes I get wrong charts(wrong images).

Is it due to roundrobin used - #SEQ(1000,1) or due to mutiple instances of my cloud app ?

Answer 1

Not sure if FF vs IE is relevant here. Rather looks like a caching issue. On Windows Azure, the ASP.NET cache is NOT shared between worker instances. If your charting logic is depending on the cache, it might be causing the problem, as multiple requests might end up on distinct web role instances.

Answer 2

I posted a solution to this problem here: http://social.msdn.microsoft.com/Forums/en-AU/windowsazuredevelopment/thread/fe6ccbdf-ec70-49f5-aef4-aada217938ed