Recycling App Pools same as Resetting Server Cache?

[Peter_Hoeft]

Hey everybody,

    We're preparing to switch our workflow User Interface from Classic to Core.  We've been reading a little about scheduling an App Pool restart, along with running IIS resets whenever they're needed.  That said, I have two questions:

Will recycling the app pools affect users on the system at the time of the recycle?

Is resetting the server cache the same thing as this, or serve the same purpose?

Thank you all for the help!  Cheers!

[Doug_Kupec · Accepted solution]

hi Peter,
Great questions on best practices with your server side components.

IIS Resets – Any active users will have their session disconnected. This will stop and start all IIS processes as well as all Application Pools. Because this restarts everything IIS related, this level of restarting is often unnecessary.

Application Pool Recycle - Any active users will have their session disconnected. This will stop and start a specific Application Pool (w3wp.exe). This is generally preferred as the impact to active users can be better managed.

An IIS Reset or Application Pool Recycle can be scheduled to occur during your nightly or weekly maintenance window.

The Application Server Cache Reset is not the same as the two procedures discussed above. The Cache Reset is for emergency configuration modifications that need to impact production during the business day. This change will impact both interactive users as well as API level processes.

The reason to consider a Cache Reset as an emergency procedure is because active users are in progress on work tasks. Depending on the modification to configuration, performing a Cache Reset has the potential to cause the data for logged in users to be in an inconsistent state. This is a result of cached data Application Server references to tasks in progress. This inconsistency can cause different users to see different information or prevent proper Workflow execution.

To prevent these types of situations, it is best a practice to update/modify process configuration during downtime, unless there is an urgent need during the business day.

I hope this information helps.

thanks,
Doug

[Doug_Kupec · Accepted solution]

hi Peter,
Great questions on best practices with your server side components.

IIS Resets – Any active users will have their session disconnected. This will stop and start all IIS processes as well as all Application Pools. Because this restarts everything IIS related, this level of restarting is often unnecessary.

Application Pool Recycle - Any active users will have their session disconnected. This will stop and start a specific Application Pool (w3wp.exe). This is generally preferred as the impact to active users can be better managed.

An IIS Reset or Application Pool Recycle can be scheduled to occur during your nightly or weekly maintenance window.

The Application Server Cache Reset is not the same as the two procedures discussed above. The Cache Reset is for emergency configuration modifications that need to impact production during the business day. This change will impact both interactive users as well as API level processes.

The reason to consider a Cache Reset as an emergency procedure is because active users are in progress on work tasks. Depending on the modification to configuration, performing a Cache Reset has the potential to cause the data for logged in users to be in an inconsistent state. This is a result of cached data Application Server references to tasks in progress. This inconsistency can cause different users to see different information or prevent proper Workflow execution.

To prevent these types of situations, it is best a practice to update/modify process configuration during downtime, unless there is an urgent need during the business day.

I hope this information helps.

thanks,
Doug

[Peter_Hoeft]

Doug, this is great - thank you! One last question, is the Application Server Cache Reset the same as the "Reset Server Cache" button within OnBase Studio?

[Eric_Nelson1]

Doug,

You mentioned that an Application Pool Recycle will disconnect sessions for any active users.
- Will the Web and Unity Client automatically reconnect or would they have to restart the client?
- If it automatically reconnects, will active users lose work they are in progress on?

I just want to be sure I understand what you mean by the Application Pool Recycle being "generally preferred as the impact to active users can be better managed."

Thanks!
Eric

[Doug_Kupec]

hi Eric,
The Unity Client can reconnect, but the user may need to push the "reconnect" button (the experience is version dependent on what the user will see in the UI). If the user's session is disconnected in the middle of processing data when the recycle happens, most likely the user will need to redo the activity. If the user is not actively processing data, than the next operation should happen seamlessly in most cases (I am sure their are some edge cases for multi-step processes that require certain state data, but this would require us to dive into details on the process).

In all cases for the Web Server, the user will need to log out and log back in again.

An IIS Reset requires all processes (i.e. Application Pools and other IIS related processes) to stop and each process needs to restart. It can take minutes of time to have all the processes shutdown and clean up, so the impact can be greater than just stopping and starting a single Application Pool. When there are multiple Application Servers on the same Windows Server, the recycle should lessen the impact to active sessions.

Hope that clarifies,
Doug