Iis – How to check how many users are online

asp.netiismaintenance

I administer a ASP.NET website that has decent traffic. In the middle of the day, I sometimes would need to either redeploy the website, change the configuration in the web.config file or make some update to the SQL Server.

In theory, when I make these changes, I can redirect the user to a "Maintainence page" that indicates that updates are in progress. But sometimes, the fix usually takes only a few seconds.

How would I check how many users are using the website and apply the quick changes when no one is online? I do have access to the web server and the database server.

Best Answer

You could monitor active connections in real-time using System Monitor (type perfmon in the Run dialog box). Add the "Web Service" counter to monitor active Web connections.

Here is a list of performance counters for IIS 6.0 (Microsoft Technet).

Related Solutions

Zero Downtime Uploads and Rollback in IIS

Here is how I would approach this problem - keep in mind I haven't done this before, it is just concepts that I tested out a little bit in my dev environment. You should be able to setup a pretty robust framework using this and some scripting in your language of choice. Basically we are going to setup a ghetto load balancing environment and use that to switch between the new site and the old site.

To get it setup, you are going to need:

IIS Application Request Routing (ARR) module
IIS Web Deployment tool (msdeploy)
3 different IIS websites (with 3 different IP addresses - just using ports or host headers might not work here)

Install ARR to begin with.

Setup the 3 websites in IIS:

Website 1 will be the site your users actually connect to, lets say http://192.168.1.1/. This is also the ARR site. Just setup an empty directory for this to point to, and put it in its own app pool. Setup the app pool to not timeout according to these instructions.
Website 2 and 3 will be the sites that actually host your content. These need to be on their own IPs and due to how ARR works, on a different port than website 1. Lets say they are http://192.168.1.2:8080 and http://192.168.1.3:8080. They should also be in their own app pools, and point to different directories on the file system (but both directories have the same content typically)

After installing ARR, there will be a new category in IIS Manager called "Server Farms" - right click that and create a new farm.

give it a name that is meaningful to you
add Webserver 2 and Webserver 3 as the servers - make sure to click the "advanced settings" button, open up the "applicationRequestRouting" category and change the httpPort to 8080 for each server
Finish the wizard - you will be asked if you want to create URL Rewrite rules - click Yes
You now have a server farm - to finish the configuration, go to the farm and click the Proxy configuration button - turn on "reverse rewrite host in response headers" and apply the changes
In IIS Manager, go to the root level server category and click the URL Rewrite button, there will be a rule that was created for your farm
- double click the rule to get to the settings
- open the Conditions box
- add a new condition for {SERVER_PORT} does not match 8080
- apply the changes

At this point you have the basics of what we need to accomplish your request. If you go to http://192.168.1.1/ you will get your website from either Website 1 or Website 2, but it will be completely seamless that there are other sites.

Now what you can do when you want to deploy a new version of your application is:

drainstop 1 of the servers in your farm (in the server farm tools, go to "Monitoring and Management", choose a server and choose "Make server unavailable gracefully")
deploy your new version of the site to the system that is offline
warmup the site that is offline using its alternate IP/port
make the site available to the farm again
repeat the process for the other server

The Web Deployment tool comes into play when you talk about wanting to script all of this. It makes it super easy to create a package for your application and deploy it from the command line. You can also then rollback that package easily if there are problems. ARR is also scriptable using the Microsoft.Web.Administration dlls.

One other thing - if you are actually on Windows 2008 R2 (which is IIS 7.5) take a look at the Application Warmup module - it should make the warming up portion of this easier on you as well.

Windows – How to you know what is w3wp.exe doing? (or how to diagnose a performance problem)

You can also use the Worker Processes UI inside IIS Manager and inspect the requests that are currently executing and see where they are getting stuck if any. Open IIS Manager->Click the Server in the Tree->Double Click Worker Processes Icon->Double click the Worker Process that is consuming CPU to see the currently executing requests in real time so that you can see which module is taking time.

Also consider using Failed Request Tracing to track some of the time per request to see where they are taking long time.

Best Answer

Related Solutions

Zero Downtime Uploads and Rollback in IIS

Windows – How to you know what is w3wp.exe doing? (or how to diagnose a performance problem)

Related Topic