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Published: Monday, February 4, 2002

How Long has the Web Server Been Up?

By Scott Mitchell


More Web Server Information at your Finger Tips
One of the coolest things about ASP.NET is its ability to use all of the classes and methods of the .NET Framework. This means that tasks that required a COM component in classic ASP can be done natively with ASP.NET. This current article shows how to determine how long the Web server computer has gone without a reboot. In Displaying Information about the ASP.NET Process, we look at how to determine statistical information about the ASP.NET process itself. In Displaying Performance Monitor Information through an ASP.NET Web Page we look at how to read data from the Windows Performance Monitor (such as free memory, CPU utlization, ASP.NET information, IIS information, etc.) and display it through an ASP.NET Web page.

- continued -

Introduction


Have you ever wondered how long your Web server has been running without needing a reboot? If you work at a Web host, or are physically close to your Web server, determining this information is very easy. However, if you Web site is hosted by a Web hosting company or if you don't have access to the actual box, finding out such information may be difficult. Well, it was difficult with classic ASP, but with ASP.NET finding out all sorts of performance information about your Web server is easy!

Determining How Long Your Web Server Has Been Running


In computer-speak, the uptime of a computer is the time between it's run since its last reboot. With older versions of Windows, sadly, this time interval was usually very low, especially compared to other operating systems (think UNIX and its derivatives) that boasted months or even years of continuous uptime. With Windows 2000 and Windows XP, though, Windows users have come to expect lengthy uptimes. For example, my personal computer usually has an average uptime of around 50-75 days.

If you use a Web hosting company, you may be interested to know just how often the machine that hosts your Web site is being rebooted. Remember, each time it's rebooted, there's an interval of time where your visitors will not be able to visit the site. Being able to keep tabs on this uptime number, if nothing else, serves as a metric for how well your Web hosting company is doing keeping your site up and running!

Determining the uptime and displaying it through an ASP.NET Web page is quite simple. The .NET Framework contains an Environment class that contains all sorts of machine-level information, such as: the machine name, the OS version, the system directory, the machine's environment variables, and (important for us) the TickCount. The TickCount is the number of milliseconds the machine has been running. It is represented as a 32-bit integer, meaning that, due to the size restrictions of such a sized integer, will be "reset" every 49.7 days. That means, after 49.7 consecutive days of uptime, the TickCount property will be reset to 0.

Displaying the number of milliseconds your Web server has been running is not that useful; rather, we'd like to know the days, hours, and minutes. We can compute these via a simple calculation:

Dim millisecondsUp as Integer = Environment.TickCount
Dim secondsUp as Integer = millisecondsUp / 1000
Dim minutesUp as Integer = secondsUp / 60
Dim hoursUp as Integer = minutesUp / 60
Dim daysUp as Integer = hoursUp / 24

Hopefully these calculations are clear. The bold part of the code uses the Environment class's TickCount property to retrieve the number of milliseconds the computer has been running. Next, the number of seconds the machine has been running is simply the number of milliseconds divided by 1,000 (since there are 1,000 milliseconds per second), the number of minutes is the number of seconds divided by 60, and so on.

When displaying this information, we have to be a bit clever, since the value of minutesUp (the number of minutes the machine has been running) might be a large number, like 6,346. We are only interested in displaying a value between 0 and 59, hence we use the Mod operator, as shown in the code below:

'Display the Web server's uptime
Response.Write("The Web server has been running for:<br>")
Response.Write(daysUp & " days, " & hoursUp Mod 24 & " hours, ")
Response.Write("and " & minutesUp Mod 60 & " minutes.")

Using the TimeSpan Class


A simpler, and more elegant way, to display the uptime of the Web server is to use the TimeSpan class. This class contains properties and methods to allow for determining differences between dates and times. (For an article on accomplishing such a task with classic ASP, be sure to read this FAQ.) By using this class, we don't need to do the division and modulo math that we performed in our above example.

'Compute the TimeSpan
Dim ts as TimeSpan = TimeSpan.FromMilliseconds(Environment.TickCount)
Dim minutesUp as Integer = ts.Minutes
Dim hoursUp as Integer = ts.Hours
Dim daysUp as Integer = ts.Days

Pretty straight forward, and without all that division. Furthermore, when displaying these values, we can just display minutesUp and not need to worry about displaying minutesUp Mod 60. (Thanks to Ryan Trudelle-Schwarz for the TimeSpan suggestion...)

The final code, and a live demo, can be seen below.


Complete Source Code
<script language="vb" runat="server">
   Sub Page_Load(source as Object, e as EventArgs)
      Dim ts as TimeSpan = TimeSpan.FromMilliseconds(Environment.TickCount)

      ltlUptime.Text = "The Web server has been running for:<br>" & _
          ts.Days & " days, " & ts.Hours & " hours, " & _
          "and " & ts.Minutes & " minutes."
   End Sub
</script>

<asp:literal id="ltlUptime" runat="server" />

Output The Web server has been running for:
-11 days, -19 hours, and -8 minutes.


Conclusion


Determining how long your Web server has been running without needing a reboot is an easy task to accomplish with ASP.NET. In fact, you can determine a myriad of other performance metrics, such as RAM usage, CPU usage, etc. through the .NET Framework by using classes to read the Windows performance tool readings. All this through an ASP.NET Web page! Perhaps a future article will cover this topic in more detail...

Happy Programming!

  • By Scott Mitchell



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