The post Try the ?nocache=1 option appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

The post APM questions to ask appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

Website Monitoring Tools

• Insping
• Updown
• Pingometer
• Uptime Robot
• Pingdom

Server Monitoring Tools

• Insping
• Monitor.us
• Nagios Core
• Ganglia
• Collectd

Network Monitoring Tools

• Nagios
• Capsa Free
• Fiddler
• NetworkMiner
• Pandora FMS

Application Performance Monitoring Tools

• Insping
• New Relic APM
• AppDynamics
• Foglight
• ExtraHop

Real User Monitoring Tools

• AppDynamics
• Dynatrace
• inspectIT
• Akamai
• Pingdom

The post Performance Monitoring Tools appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

Cross Platform – J2EE and .NET Static Code Scan

1. SonarQube – Free
   HP Fortify –  Paid

The post Static code analysis appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

The post Quick troubleshooting of slow responsiveness on an IIS–SQL Server app appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

1. Fiddler (free)

2. Visual Studio Ultimate – Web Performance Test Editor (comes with VS Ultimate)

Fiddler is really easy to get started with.  There are several online videos.  Here is a blog post on getting started with Fiddler and load testing

RESOURCES

1.      Fiddler Download

2.      Load Testing with Fiddler

Visual Studio Performance Test Editor

The post Some options for load testing web applications appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

CAUSE  – If your request contains a ‘long-running’ task – and you end up sending multiple such requests to IIS, pretty soon all available threads in IIS are TIED UP processing these requests.

POSSIBLE SOLUTIONS :

Web Gardens

You can assign more than one IIS worker process for a given application pool (this is called a Web Garden). What this does is effectively provide you with more threads to use. You can accomplish the same thing by increasing the maxThreadsPerCPU (set to 0 for max), however, this is probably set as 0 anyway. So your next step is to create multiple worker processes – each of which uses up all the threads it can. Note that this workaround works only if your ‘long running task’ is not CPU intensive. If it is chewing up CPU resources, creating a web garden (more processes that chew up the CPU) will only make the problem worse. For tasks that simply chew up threads – and are not CPU intensive (e.g. Database UPDATES), the WEB GARDEN workaround is an acceptable one.

IIS 8.0 Onwards

The first question to ask is – what is your ASP.NET code doing that is causing this slow down? Whatever this long-running request (task) is (in your asp.net code), you can consider moving it to an IIS background worker process.  This is a new feature available in IIS 8.0.

IIS 7.X

There are certain configuration parameters that you can utilize to control the number of threads used per IIS worker process . These include the following parameters:

<system.web>
   <applicationPool maxConcurrentRequestsPerCPU="12" maxConcurrentThreadsPerCPU="0" requestQueueLimit="5000"/>
</system.web>

What are some long-running tasks that chew up threads (but not CPU)?

• Applications that make long running database requests
• Applications that have  long-running, synchronous requests (transactions)
• Applications that have  long-running , network intensive transactions

Overview of Application Pools and Worker Processes

1. One IIS server may have multiple application pools.
2. One web application binds to one application pool.
3. One application pool may have more than one worker process (when Web Garden is enable).
4. One worker process can have multiple app domains (an asp.net only concept). One app domain lives only in one worker process.
5. One app domain may have multiple threads. One thread can be shared by different app domains in different time.

The post How to handle an unresponsive IIS web application appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

Some of the more important ones include:

Processor:

Processor\% Processor Time (This counter is the primary indicator of processor activity. High values many not necessarily be bad. However, if the other processor-related counters are increasing linearly such as % Privileged Time or Processor Queue Length, high CPU utilization may be worth investigating)

• Less than 60% consumed = Healthy
• 51% – 90% consumed = Monitor or Caution
• 91% – 100% consumed = Critical or Out of Spec

\Memory\Available MBytes

(Available MBytes is the amount of physical memory available to processes running on the computer, in Megabytes, rather than bytes as reported in Memory\Available Bytes. The Virtual Memory Manager continually adjusts the space used in physical memory and on disk to maintain a minimum number of available bytes for the operating system and processes. When available bytes are plentiful, the Virtual Memory Manager lets the working sets of processes grow, or keeps them stable by removing an old page for each new page added. When available bytes are few, the Virtual Memory Manager must trim the working sets of processes to maintain the minimum required)

• Low on available memory – less than 10% available
• Very low on available memory – less than 5% available
• Decreasing trend of 10MB’s per hour. This could indicate a memory leak.

\Memory\Pages/sec

(If it is high, then the system is likely running out of memory by trying to page the memory to the disk. Pages/sec is the rate at which pages are read from or written to disk to resolve hard page faults. This counter is a primary indicator of the kinds of faults that cause system-wide delays. It is the sum of Memory\Pages Input/sec and Memory\Pages Output/sec. It is counted in numbers of pages, so it can be compared to other counts of pages, such as Memory\Page Faults/sec, without conversion. It includes pages retrieved to satisfy faults in the file system cache (usually requested by applications) non-cached mapped memory files)

• High pages/sec – greater than 1000 (If it’s higher than 1000, the system is could be beginning to run out of memory. Consider reviewing the processes to see which processes are taking up the most memory or consider adding more memory)
• Very high average pages/sec – greater than 2500 (If this is greater than 2500, the system could be experiencing system-wide delays due to insufficient memory. Consider reviewing the processes to see which processes are taking up the most memory or consider adding more memory)
• Critically high average pages/sec – greater than 5000 (If this is greater than 5000. If so, the system is most likely experiencing delays due to insufficient memory.

The post Some important server perfmon counters to monitor appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

1. Click Rules > Customize Rules….
2. Inside the OnBeforeRequest handler, add

oSession.oFlags["x-AutoAuth"] = "domain\\user:password";

The post Configuring an authentication header in fiddler appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

This is just a quick note to highlight a commonly used web testing metric for making an initial determination of where the source of bottleneck(s ) might be.

TTFB

Most commonly, testers measure the total response time for a web page. This is the total time for the server to respond – and then the page to load (completely) in your browser. While this is useful, it does not tell you how long the server actually took to respond to your request (since it includes BOTH server and CLIENT (browser) side load times).

To simplify this measurement, another metric called the Time to First Byte (TTFB) is used.  This is JUST the server’s response time – not including the page load time. 

The significance of TTFB is that it helps us make a quick determination of how fast or slow the server is at handling a single request.

Server Side Issue / Slowness

A high TTFB implies a server side problem. If it is taking the server a long time to return the first pieces of data, chances are that there is/are server side bottlenecks.

Client Side Bloat

A low TTFB – but a high page load time, would mean there are front-end issues (CSS, images, scripts). This is especially useful since these issues can be easily and quickly addressed (by techniques such as image compression, CSS and javascript compression etc.).

Free Tools to determine TTFB

Fiddler

Using something called a Timeline View in Fiddler, one can see the entire lifecycle of a server’s response (new to fiddler or load testing?). Here is an example of an actual timeline showing both TTFB and total response time (including client side page load time). In this example, the TTFB is relatively short – and the total response time (including page load) is relatively long. This points to a client side bloat (excessive javascript , css and image sizes…). To figure out exactly how large each of these client side pieces are – you can use the other tool listed below – WebPageTest.org.

Fiddler’s timeline view – showing TTFB and Total Response (including Page Load) time

WebPageTest.org

This tool gives detailed information about various pieces of your web page – and how long each took to load. This complete picture is presented in a sequential timeline showing each component’s loading start and end times. Such a view is called a waterfall view. Here is an example of a waterfall view for my website’s home page – anujvarma.com.

Summary

A metric called the TTFB can be useful in determining slowness of client or server side components. This metric can provide a quick assessment on whether the slowness is server side or client side or both.

Several free tools (notably Fiddler and WebpageTest.org) provide these metrics. Using waterfall views (timeline views), one gets a detailed breakdown of each component (images, css, js…) and how long each took to load.

The post Using TTFB to distinguish between server side and client side page load issues appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.