Note: This blog post is from 2010. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.

It's a first cut. While there are couple of concerns that will come to mind for some readers, and I try to address those at the end, it does work for me and has helped improve my server's stability and reliability, and it's been used by many others.

Update in 2020: I have changed the 503 status code below to 429, as that has become the norm for such throttles. I had acknowledged it as an option originally. I just want to change it now, in case someone just grabs the code and doesn't read it all or the comments. Speaking of comments, do see the discussion below with thoughts from others, especially from James Moberg who created his own variant addressing some concerns, as offered on github, and the conversation that followed about that, including yet another later variant.

Update in 2021: Rather than use my code, perhaps you would rather have this throttling done by your web server or another proxy. It is now a feature offered in IIS, Apache, and others. I discuss those in a new section below.

Background: do you need to care about throttling? Perhaps more than you realize

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Note: This blog post is from 2010. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.

It also gives me a chance to offer some props for the site of the company behind the tools, SolarWinds, which again many may find valuable in educating not only about the tools but the topics that the tools help with.

The free SAN and VM monitoring tools

• SolarWinds Free SAN Monitor - keep a close eye on the performance & capacity of your storage arrays and become a storage superhero!
  Note also:
  • Intro video
  • Or step up to their commercial Storage Profiler - Multi-Vendor Storage Performance Monitoring
• VM Monitor - continuously monitor a VMware® ESX Server and its virtual machines with at-a-glance virtualization health statistic
  Note also:
  • Intro video
• WMI Monitor - monitor your Windows® apps and servers in real time, using built-in, community-sourced, and customizable application templates!
  Note also:
  • Intro video

I haven't yet used them myself, so this isn't so much a recommendation of the tools but rather a recommendation that you consider them if you are interested in what they have to offer.

The company offers still more free tools, as well commercial ones of course.

A company that gets how to educate you about their products

You may have noticed above that I offered as well links to videos about each product. SolarWinds has really done a great job offering educational resources, especially videos, and organizing them into categories such as tech talks, webcasts, and more.

Indeed, if you may be new to network management (which can be a broad and/or deep subject, appealing variously to generalist IT geeks and hard-core network admins), they offer lots of compelling introductory resources, including their geek guides and even certification training . Of course they also have a helpful blog and twitter feed.

Just as I previously praised the Mura folks as a "company who got it right" in terms of setting up a compelling, informative web site for IT folks, I really have to say the same for the SolarWinds folks. Congrats, and thanks.

Note: This blog post is from 2010. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.

Several Performance Advantages, and Failover As Well

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Note: This blog post is from 2010. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.

I also discuss below the key varscoper tool which you will want to use to help assess and indeed correct your own code.

(Update in 2022, 2019: while the many resources are indeed all quite old now, they all still apply, and most still exist. Where needed, I recovered them from the good ol' archive.org, an awesome resource for finding old content, as I've written about before.)

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Note: This blog post is from 2010. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.

While you can find the details (and optional RSVP info) on the meetup event page, I'll repeat the description to save you having to go there:

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Note: This blog post is from 2010. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.

"CF911: Stack Tracing CFML Requests to Solve Problems"

Regardless of what CFML server monitoring tool(s) you have, or even if none, did you know that you can use a feature called "stack traces" to be able to pinpoint the exact line of code that a CFML request is running at any time? Did you know how to use that information to troubleshoot performance/stability problems? Do you know how to obtain that information either manually or automatically (such as during a crash while you're not watching)? Do you know how to obtain that information in any of the CFML Server Monitors (FusionReactor, SeeFusion, the CF8/9 Enterprise Server Monitor), or with free command line tools? And how to do this for any CFML engine (CF, Railo, BlueDragon, etc.)? Do you know how to interpret the information once you get it?

In this session, veteran CF troubleshooter Charlie Arehart will help remove the mystery from using stack traces. It really is amazingly simple with the right tools, and it can be incredibly useful to solve otherwise thorny problems, once you understand how to interpret the information.

Of course, I'm thrilled to be heading back to Minneapolis. I spoke there previously in 2008 and 2007 but couldn't attend in 2009. It'll be great to see all the fine folks who run and attend this unique conference.

BTW, I just saw also that CFUnited announced another round of topics accepted today and I see a topic whose title if very similar, "How to Read a Stack Trace", by the inimitable Daryl Banttari. It's hard to tell from his brief description how similar these will be, but Daryl is awesome so I'm sure I'll learn much from his. (I was literally just about to offer mine as another CFUnited submission but now won't of course. :-) Hopefully another of my submissions will be accepted, so I can keep my streak of having spoken at every CFUnited since they started.)

Anyway, the good news is that whichever conference you go to, this important (and often misunderstood) topic will be covered! :-)

Note: This blog post is from 2009. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.

What was so curious was that my local mail client (Outlook) was configured with the exact same servername, username, password, and port, and ran fine from the same laptop on which CF was running. Both were trying to send email via the remote mail server. Why would CFMAIL fail when Outlook would work, both connecting from the same machine to the same SMTP server with the same connection parms?

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Note: This blog post is from 2009. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.

Before you dismiss the idea outright, consider the description below, and if you have an hour to spare, come check it out. You may learn something very surprising. Some of the things I'll discuss are not often talked about, from my observation. Yet I help a lot of people who are hurt by them.

I'll add, also, that out of nearly 80 sessions I've hosted, I've only spoken a few times. The meetup is definitely not "the Charlie show". Thanks to all the many other speakers who have come out the past couple of years.

My Session Title: Sessions and Clients and Crashes, Oh My!

Description: You may be suffering and not even realize it. As a consultant, I focus on helping people troubleshoot CF problems, and one of the most common (and least appreciated) problems people suffer are those related to having too many active sessions in memory or a high rate of creation/update of client variables (whether in registry or database). EVEN IF YOU'D SAY YOU DON'T USE SESSIONS OR CLIENT VARIABLES, this may impact you.

In this session, veteran CFer Charlie Arehart will explain the problem. Using live demonstrations and offering code you can use yourself for free, he'll show how to identify both the extent of and the cause of the problems, and various solutions. The concepts provided will apply to any version of CF (or BD or Railo).

To RSVP (not required) or to learn more about the meeting, including the URL to attend, see the event page.

Update:The recording for this is available here.

Note: This blog post is from 2009. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.

Basic CF Monitoring in Nagios

First let me share that if you've not explored monitoring CF with Nagios at all, here's at least one blog entry from 2005 discussing that. (A more recent one, at http://profec.net/2009/01/12/monitoring-coldfusion-with-nagios/, which I used to list here, is no longer responding, nor could I find it on archive.org.)

Of course, you can easily use Nagios primarily to report whether CF's up or down, but you can also monitor basic statistics such as are provided via CFSTAT (also available on Windows via Perfmon, which also exposes generic stats about all processes), as demonstrated in that blog entry.

But you may have noticed that, if you run the Multiserver (multiple instances) version of CF, those CFSTAT and Windows Perfmon Stats aren't available on that version of CF.

So what to do if you wanted to monitor more about what's going on inside of CF?

FusionReactor Nagios Plug-in

If you're running FusionReactor Enterprise, you can now get that additional information via the free FusionReactor Nagios Plugin. It's a perl app that when implemented will expose certain key statistics in a way that Nagio can process them (and some are things that CFSTAT and the CF Permon stats don't report):

• Count of current running requests, and total count of all requests run
• Count of request queued by FusionReactor
• Average request runtime (since server start), and Recent request runtime (in past 60s, by default)
• Count of recent slow pages
• Memory free in bytes and percentage
• Memory Total and Max
• Instance and System CPU Use percentage
• Count of recently completed JDBC requests

Note that this is technically community-contributed feature (from an Intergral employee, David Stockton), not a supported feature.

If you're running or are interested in FusionReactor Enterprise, check it out.

Note: This blog post is from 2009. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.

The problem outlined here has to do with being careful when you're modifying CF to enable/disable RDS (or doing any edits in the [cf]/wwwroot/WEB-INF/web.xml file that controls it.) This applies to CF 6, 7, or 8.

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