Unity Not Being Disposed Causing Server Lockup?

We have a server farm of about 40 servers that we roll code to every couple weeks. One thing we noticed when we roll the code live is after deploying the assemblies and performing an IIS reset and put it back in the BigIp (F5) and it receives traffic the server will lockup for about 10 minutes and clients will just spin until an eventual timeout.

Looking at the perfmon we can see a dram开发者_运维技巧atic spike in number of finally's and number of pinned objects btw which lead me to investigate memory issues.

So one thing I started looking into it our Unity IoC configuration. In the global.asax.cs we are registering about 15 interfaces where most are using the ContainerControlledLifetimeManager to manage the lifetime. Normally there is never a problem with the code except in this ten minute window so my first thought was a memory or resource management issue.

Does anyone know if you have to explicitly Dispose() of your Unity Container or is this handled by Unity automagically somehow? I noticed today that there was no Dispose wiring in place for Application_End so my thought was maybe when the servers are brought back on after the IIS reset there is a Unity or object resource issue until the GC comes around and frees the memory (the ten minutes it takes to come up).

Any help is appreciated!

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Performing an iisreset will kill the currently running w3wp.exe process, so it's unlikely that not properly disposing of unity objects in Application_End would cause performance issues on startup. It is possible that the old web process doesn't properly release file system or other resources the new web process depends upon, but I think you'd see file access or some other errors if that were the case.

Since you're performing an iisreset, I would look closely at the code that runs when the application starts for the first time. Maybe there are some components that take alot of time to start up (i.e., say there is a singleton type class that downloads and caches a bunch of stuff from the database) that are causing the slow down, possibly only when combined with the stress of handling all of the waiting HTTP requests. Also, keep in mind that ASP.NET will incur a bunch of overhead as it compiles the application to be used the first time. Since it seems that your web application is behind a load balancer, you may want to come up with a way to "prime" the application on each individual web server before you add that web server back to the load balancer, which could be accomplished by just loading a page locally on that web server. Priming the application would allow the web app initialize itself without having to handle any outside requests, which should improve the startup time.

Long story short, I would investigate startup issues and see what I could tune there before I focused on shutdown issues.