My topic for CFUNITED 2010 was selected! I'll be speaking about the new Excel generation features in CF9; much easier and more flexible than generating the XML or HTML used to be.

Thank you to everyone who voted for my topic.

See you all at Lansdowne.

Congratulations to Liz Frederick on becoming Adobe Community manager. I wish her great success in her new role. It is a tribute to the TeraTech culture of creativity and promoting from within, that Liz was able to go from being a graphics intern in 2001 (helping with CFUN) to COO of Stellr in 2008. With her creativity, quickness to learn and hard work she co-created CFUnited together with me and some members of the ColdFusion community. This year the Stellr team made CFUnited-09 the best rated yet by attendees.

Fortunately Liz is very organized and leaves the Stellr conference team with pages of schedules, procedures, budgets and a full business plan for CFUnited. I have every confidence that Stellr together with the CFUnited advisory board will produce an excellent event next year. And as both the founder of CFUnited and an advisory board member I am here to help in any way necessary.

My CFUnited presentation on "Dynamic Load Testing with Webserver Stress Tool" went well. Thanks to everyone for the good feedback. 

My presentation, source, and testing scripts will be posted on the CFUnited site soon after the conference.

Congrats to the 3 raffle winners: Steven Focht (Webserver Stress Tool 7), Abram Adams (WST), Bryan Modders (FusionReactor).

Paessler will be contacting the WST winners soon with the license info.

Thanks again to Paessler and Intergal.

CFUnited is next week!

I'll be presenting on Wednesday on "Dynamic Load Testing with Webserver Stress Tool". I'll be covering Basic, parameterized, and scripted load testing. It's a fairly inexpensive tool, but can do some powerful testing.

This week I also found out I'll be able to raffle 3 software licenses: 2 licenses for Paessler Webserver Stress Tool, and 1 for FusionReactor server monitor! ($1000 worth of software). Licenses sponsored by Paessler and Intergral, respectively.

Topics:

• Test Types
• setting up a set of URLs
• Multiple users
• URLs bound to a dataset (parameterize the tested URLs, merge with a dataset; one set for each user)
• Scripting, instead of list of URLs
• Simulate multiple simultaneous CF sessions
• How to simulate AJAX calls
• Test results and logs; where's the most useful information

Executive Summary:

Why send your developers to CFUnited?

• Give your company a competitive advantage by equipping your team with a wide range of new concepts, skills, techniques and best practices.
• Arm your company with the knowledge and experience of the industry’s top experts.
• Avoid project disasters by making your team aware of what’s available, what’s hot, and what’s not.
• Build a free support network for your team by providing them with industry contacts and resources.
• Improve team productivity and dramatically improve developer moral to boot.

During a recession it is the smart manager who makes calculated investments to get ahead of the competition. Bring valuable insight and knowledge in-house by investing in your development team today.

Table of Contents:

• What the Pros Say
• Statistics
• Topic Tracks
• Highlights
• Benefits
• Prices
• Manager's Credo

To find out more please visit: cfunited.com/images/CFUnited2009_managerguide.pdf

This years ColdFusion United was great!  Those who came were a part of history, the 10^th annual CF United conference, and the first one ever held at the DC Convention Center.  People have said this was the best one ever with its range of topics and speakers as well as the events and antics being put on splendidly.

For all of those that could not make the conference, we are in the process of putting different presentations on the CFUnited websites so you can download them and watch them at your leisure.  This is also useful for those people who just LOVED some of the presentations and want to watch them over and over again.  To access these, go to www.cfunited.com/blog and scroll down to the entry dealing with “Presentations Recorded on Connect.” 

In addition to this, there were different interviews and roundtables recorded and also uploaded so that we all might have the pleasure of listening in on them.  Thanks to Brian Meloche for recording these, some of the people interviewed are John Farrar, Liz Frederick and TeraTech’s President Michael Smith.  To hear these interviews, go to www.cfconversations.com.

Thanks to everyone who helped in making this years’ CFUnited the best one ever!  We’ll see you all next year!

My presentation on HA-Clustering at CFUnited actually consisted of two parts.  Firstly there was the PowerPoint bit which I uploaded to the CFUnited server and then there was the practical part which I would like to overview here for those who could not make the event.

I had intended to use two VMware copies of Windows 2003 Enterprise (32Bit) with Windows Network Load Balancing (NLB) running as the web server clustering mechanism,  ColdFusion Enterprise 8.01 and MySQL 5.0.  I attempted this on my Windows XP notebook with 3GB Ram and after several attempts I gave up because I just could not get enough responsiveness, I could never have gotten through the presentation effectively.  However, I do intend to attempt this again, in future.

Instead I reverted to running the tests on my notebook and the details are as follows:

• System - Dell Inspiron E1705 with 3GB Ram running Windows XP. 
• CF Version - ColdFusion Enterprise 8.01, installed in the multi instance manner with two instances clustered with RoundRobin algorithm.
• Servlet Container - JRun 4 Updater 6.
• JVM - Sun 1.6 (aka 6).
• Web Server Apache 2.0.59
• Test Application - cfwhisperer blog lab copy based on Mango blog.
• Load Test Tool - Paessler Web Stress Tool.
• Server Utility - SeeFusion version 4.0.7

I created a load test script by simply browsing the lab copy of the cfwhisperer blog in the URL recorder inside the Paessler Web Server Stress Tool and saving the URLs; this took me about 5 minutes total  and I had a very usable test script, that is one of the reasons I really like the Paessler tool.  I recorded 18 clicks in total as I have found around 20 to be optimal, for most test scenarios. As my presentation was only 60 minutes total I only showed one 10 minute test.   I kicked off the test which was running against the Apache web server which I connected to the two instance CF cluster with the wsconfig GUI utility.  So this was a 10 minute load test with 20 concurrent vUsers with 8 second think time between clicks.  As the test was running I first stopped one instance and we immediately observed the response times climb from an average of 300 milliseconds to a peak of over 20 seconds and then fall back to 300 milliseconds, this took around 30 seconds and although response times went up we still responded to requests.  I left this for a couple of minutes then restarted the stopped instance there was no similar slowdown as the instance came back, but we did see a slight rise to 600 milliseconds.  I then repeated the exercise by stopping the other instance and we observed similar results. 

My intention is to at least repeat this at cfdevcon in Brighton, England in September, 2008 and hopefully extend it a bit if I can.

This is the second in a series of blog posts leading up to my presentation on Clustering at CFUnited on June 20, 2008 at 2:00PM.  Clustering has been available to us in two apparently different forms.  Hardware Clustering and Software Clustering.  I say apparently different as some digging reveals interesting items, particularly as they relate to the current Software Clustering offered with ColdFusion – JRun.

Before looking more deeply into those issues, I wanted to lay out some basic differences between Hardware and Software Clustering.  In my view a Hardware Clustering system exists when there is a dedicated piece of hardware whose only job is to handle Clustering (Fail-Over and/or Load-Balancing).  One detail of note here, the Hardware Clustering device needs Clustering Software to operate. 

Software Clustering typically means that the Clustering Software is installed on an existing server, not a dedicated Hardware device.  One noted example of Software Clustering is Windows Network Load Balancing (aka NLB).  This is a bit of a misnomer, as this is a Clustering mechanism which includes Load-Balancing as well as Fail-Over.   Another example of Software clustering is the Clustering offered in ColdFusion-JRun which is actually based on J2EE standards.

If we dig a little deeper into the current J2EE clustering used in ColdFusion and JRun; since CF moved to Java with the MX version forward.   We see what I would class as a subset of full Software Clustering.  The reason I believe this is that J2EE clustering as applied the CF-JRun is a sub-set of Software Clustering is that it is purely peer-to-peer with no overall service watching all Cluster members.  Typically we would not only have multiple ColdFusion severs-instances but also multiple web servers or we would not have full redundancy.  Fail-Over over is not covered at the CF-JRun level if a Web server fails.  There has to be a higher level system to do this such as Windows NLB or a Hardware Clustering device.  As an historical point;  prior to MX, ColdFusion-JRun had a much more fully featured Software Clustering system called “ClusterCATS”, this did embrace to concept of a central monitoring-management service and Web server Fail-Over.  This was always tricky though if ColdFusion was deployed in the “distributed-mode” where the Web server and ColdFusion were on different physical devices. 

The last consideration in this piece, is when would we use Hardware or Software Clustering or both.  Typically Hardware Clustering scenarios are much more robust than Software Clustering, as that is their only job in life.  Having said that; Windows NLB claims support for up to 32 servers.  Going back to the Allaire-ColdFusion clustering, ClusterCATS, our testing showed that 8 servers was a good point to consider Hardware Clustering. 

Lastly, the overall term here is “Clustering” and within Clustering we have Fail-Over and Load-Balancing so the often used term “Load Balancing Device” should actually be “Clustering Device”.

I will be presenting at CFUnited on Friday June 20, 2008, on the subject of High Availability (HA)-Clustering for ColdFusion/JRun applications and I intend to make this as practical as possible. Having spent many years travelling the world helping to fix slow or unresponsive ColdFusion applications, I see HA as a natural progression to this and in fact Load-Balancing, which is a part of Clustering, has a direct impact on improving performance.

There is a point, often overlooked by even the manufacturers of clustering/load balancing equipment. Clustering is the overall term which, in my opinion, applies whenever two items or more appear as one, to the users. In our world, that typically means multiple web servers, with multiple application and database servers.

With this aspect of Clustering there are two services which are a part of the Clustering; Fail-Over and Load-Balancing. In my experience Fail-Over is always present, meaning if one member of the Cluster fails the remaining members ensure that continuity of service is maintained. This is a prime function of a Cluster.

Load-Balancing is the apportioning of load around members of the Cluster, typically an even distribution of the load is what is required. The most even distribution is via Round-Robin which means each single request moves around the Cluster members, like this (this example shows a 3 member Cluster):

• USER 1 > REQUEST1 > CLUSTERMEMBER1

• USER 2 > REQUEST1 > CLUSTERMEMBER1

• USER 1 > REQUEST2 > CLUSTERMEMBER2

• USER 2 > REQUEST2 > CLUSTERMEMBER2

• USER 1 > REQUEST3> CLUSTERMEMBER3

• USER 2 > REQUEST3> CLUSTERMEMBER3

• USER 1 > REQUEST4 > CLUSTERMEMBER1

• USER 2 > REQUEST4 > CLUSTERMEMBER1

This is the most evenly balanced Load Balancing algorithm and as I mentioned above is the Round-Robin algorithm. Problems can occur with that algorithm if there are user specific items in memory on one of the Cluster members, for instance in memory session state variables. If USER1 has logged in to CLUSTERMEMBER1 above and their details are in session variables on CLUSTERMEMBER1 when users next request takes them to CLUSTERMEMBER2 those in memory session state variables will not be there. My preference for the optimal Load-Balancing algorithm is Round-Robin with Sticky Sessions. In the case a user “sticks” to a Cluster member as follows: 

• USER 1 > REQUEST1 > CLUSTERMEMBER1

• USER 2 > REQUEST1 > CLUSTERMEMBER2

• USER 1 > REQUEST2 > CLUSTERMEMBER1

• USER 2 > REQUEST2 > CLUSTERMEMBER2

• USER 1 > REQUEST3> CLUSTERMEMBER1

• USER 2 > REQUEST3> CLUSTERMEMBER2

• USER 1 > REQUEST4 > CLUSTERMEMBER1

• USER 2 > REQUEST4 > CLUSTERMEMBER2

  This is not quite as evenly balanced as Round-Robin alone but unless there is a failure of one Cluster member the user will not lose their session state variables and the load balances across all Cluster members eventually.

This article serves as the first in a series of posts leading up to the CFUnited presentation and my next one will delve into differences between Hardware and Software Clustering.