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I'm troubleshooting some memory issues we're running into with a heavily used ASP.NET site hosted on IIS6. Intermittently we have to manually recycle our application pool (process) to resolve issues in browsing the application and its been increasing over the last few months. I analyzed our web logs and found some interesting info:

  1. At the times where performance suffers most, I see that also correlates with the number of concurrent user sessions.
  2. It seems that user activity and # of hit does not matter as much as the number of sessions because there are days with HEAVY user activity (hit-wise), but no recycle was needed. The number of sessions were low during those times. Conversely, lighter usage but more user sessions ultimately meant a recycle.

Here is my question: Considering the info above, is there some overall memory limit for session data that we're hitting??

I'm thinking that the more user sessions created, the more memory is allocated per session and at some point we're exhausting the resources, which gets resolved with each recycle.

Does that theory make sense? Any help is appreciated. Thanks!


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llet me just say this is the most non-info request today. Not even a mention of what version of iis: Ok, here we go - how is your IIS configuration? Start by calling your admin and asking for the operating system version. – TomTom Apr 25 '11 at 19:34
?? I clearly say 'IIS6' - please read the post. OS is W2k3. What other info should I provide that would assist? – tresstylez Apr 25 '11 at 19:40
That one i overlooked ;) Funny. – TomTom Apr 25 '11 at 19:41

1 Answer 1

The amount of memory depends on which version of the OS you are using. If you are using 64 bit version then your application can reference up 16 TB (or the available memory). If you are using 32 bit version then your application can reference up to 4 GB (but only 2 GB of user memory). Here is a breakdown between the two OS types:

The size of session memory will vary depending on how much data is stored into it and what type of session is used (ex. InProc vs. SQL).

What problems are you experiencing with your application?

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Thanks for the reply. Sessions are InProc and server is Win2k3/32 Bit. Basically, the application performance suffers and users start seeing timeouts and various other memory related issues. – tresstylez Apr 28 '11 at 19:39
Update to a decent modern server asap, then take advantage of multiple processes per server (web farm setup). 3gb / process and one process per core will make the imit go up a LOT. – TomTom Nov 15 '14 at 9:25

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