Significant slowness due to server when starting an ASP.NET MVC application

[Guest /u/tbz48]

Hi,

 

I have two dedicated servers with a hosting provider for shared hosting of websites using IIS (SQL Server + IIS, applications in ASP.NET MVC). Both servers have the same hardware configuration and are up-to-date with Windows Server 2016. For clarity, let's call them : - Server A - Server B

 

Problem:

 

• Server A: All applications run normally with fast loading times.
  
• Server B: Although all applications run, they experience significant slowness at startup and on the first load of each cshtml page (which makes sense in an ASP.NET MVC application as some sort of cache needs to be built, but it is abnormally long on this server). Specifically, the startup time is almost 3 minutes on Server B compared to less than a minute on Server A for the same application.
  

[HEADING=2]Details:[/HEADING]

 

For two identical applications hosted on both servers (without communication between them, simple duplication for testing), the application startup is very slow to get the first page displayed on Server B. The first page load is abnormally slow on Server B, about twice as long as on Server A. The second load is faster but still slow compared to the other server.

 

[HEADING=2]Hypotheses and Checks:[/HEADING]

 

I wondered if Razor compilation could be the cause, for example:

 

• Cache creation issue?
  
• Slow disk access?
  
• Problem with the "Temporary ASP.NET Files" folder?
  

 

I have already checked several elements:

 

• Configuration of IIS application pools
  
• General IIS configuration in the machine.config file
  
• No parameter seems to explain this performance difference.
  

[HEADING=1]Interesting Facts:[/HEADING]

 

Server Load:

 

• Server A is more loaded than Server B (but is faster than Server B...).
  
• Server A has a higher average CPU consumption than Server B.
  
• Server B is not overloaded and CPU usage is generally below 20%.
  

[HEADING=1]Differences between the two servers:[/HEADING]

 

Server B has some older versions of our production ASP.NET V2.0 applications which run on separate application pools.

 

Public bandwidth:

 

• Server A: 1 Gbps outgoing, 1 Gbps incoming
  
• Server B: 1 Gbps outgoing, 500 Mbps incoming
  

 

Remarks: Applications run normally on both sides except for this startup slowness issue. I don't think the differences mentioned above can have a significant impact on performance.

 

What steps can I take to identify and resolve the bottleneck causing the startup slowness on Server B without disabling the server, given that it is used in production?

 

UPDATE: I've just installed a new dedicated server with a single site hosted on IIS, the problem is also present. this reinforces my thinking that it's probably a configuration in IIS that I'm not aware of.

 

Thanks for your help :)

 

submitted by /u/tbz48

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