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Effective Web Performance – Will A CDN Really Solve The Problem? – UPDATED!!!!

Content Delivery Networks (CDNs) have been available for over a decade, with companies leaning on these distributed networks to accelerate the delivery of their content, absorb the load of the peak traffic periods, and help deal with the problem of geography. During my career I have helped companies assess and evaluate CDN solutions so that they understood the performance improvement benefit they would receive for the money they were spending.

But a something bothered me during these evaluations. I felt that companies were rushing into the decision because it was the “right” thing to do, that their site could only get faster if they used a CDN. This rush often left question unasked and unanswered.

In this post, I want to provide 4 questions that you should ask before deploying a CDN, questions that will help you ensure that a CDN is the performance improvement solution you need right now.

Is the performance issues due to slow application components?

If the performance issue can be tracked down to application elements, then a CDN is likely not the immediate starting point for you and your team. If generating dynamic content or database lookups are causing the performance issue, this is on you, in your datacenter.

CDNs do not make slow applications run faster; CDNs move bits to customers faster more efficiently.

[UPDATE: There are now CDN solutions that can move processing to the Edge (see Akamai Edgeworkers)]

How are we measuring page response times?

If you are measuring response times using the load time of the entire page, then you may be inflating your response times by including all of the third-party content that has been included. You may want to set up parallel measurements that allow you to compare the full page with a page measurement that only includes the content you are directly responsible for managing. If you find that third-party content is slowing down your pages, then a CDN can’t help you.

Full page load times only give you one performance perspective. Modern performance measurement teams need to understand how long it takes for a page to be ready and usable for the customer – the perceived rendering or page ready time. What you could discover is that customers can do 90% of what they want on your page well before all of the content fully loads. If this is true, than the perceived load time for your company to determine that a CDN isn’t necessary right now.

[UPDATE: Google’s Web Vitals metrics are an example of how far the industry has evolved since I wrote this post a decade ago. As well, ensure that your organization does not have tunnel vision on a single performance metric!]

Have we done everything to optimize our own performance?

Often companies choose the easy way (CDN) to solve a hard problem (improve performance). Unfortunately, the easy way can be more expensive than taking the time to design pages and content that ensure long-term and sustainable performance. A CDN could mask a bad design until it slows down so much that even the CDN can no longer help.

Measure your page and challenge the devops team to tweak the exiting design until they don’t think they can get any more performance out of it. Then, during your CDN evaluations, set up measurements that compare the performance of origin and CDN delivered pages. You might find that making the pages as fast as you possibly can before purchasing the services of a CDN make the difference between the origin and CDN times less dramatic than they would have been before optimization.

[UPDATE: I have been doing web performance for 23 years and organizations are still challenged with the design and implementation of performant web applications before they reach the CDN. If the median TTFB for key pages is greater than 500ms, start there.]

Can we effectively estimate if the CDN cost will be offset by an increase in revenue?

CDNs don’t come cheap, so choosing to deploy a CDN better pay for itself over time. Challenge the CDNs you are evaluating to present you with ROI calculations that show how their service more than pays for itself and case studies (or customers) that prove that the cost of the CDN was offset by a business metric that can be easily tracked.

Summary

Don’t misunderstand the questions I am posing here: I am still a strong advocate for the use of CDNs. However, the days of companies simply purchasing the services of a CDN because it’s the “right thing to do” are long over.

As companies evolve their perspective on web and mobile performance, they need to ensure they have done everything they can to make their own applications faster. Once the hard work of tuning and optimization is complete, the process of choosing a CDN must include deeper, more probing questions about the performance and business benefits that come along with the service.

Tips for Securing WordPress

I spent much of the morning tracking these items down, so I thought I would share them here

Let’s start with blocking access to the any idjit that wants to try and edit the .htaccess file

<Files .htaccess>
   Order Deny, Allow

## Really? You didn't think I would do this?
   Deny from all
</Files>

Next, let’s shut down the xmlrpc.php file. Mostly unused these days, but can serve as an entry point for more idjits.

[NOTE: If you use JetPack, you may have to open this up to the Auttomatic IPs that make the automated backup requests.]

<Files xmlrpc.php>
   Order Deny,Allow

## No soup for you!
   Deny from all
</Files>

Finally, let’s IP block the access to the wp-admin area. One addition to this is my public IP address. The reason I added this here is that if you access your WP instance by its hostname rather than its IP, your requests will actually go in and out of your router. They will appear with the public IP address even if they originate from within the private IP range.

<IfModule mod_rewrite.c>
   RewriteEngine on
   RewriteCond %{REQUEST_URI} ^(.*)?wp-login\.php(.*)$ [OR]
   RewriteCond %{REQUEST_URI} ^(.*)?wp-admin$

## Your local private IP range
   RewriteCond %{REMOTE_ADDR} !^192\.168\.1.

## Your external IP
   RewriteCond %{REMOTE_ADDR} !^[IP ADDRESS REGEX HERE]$

## What to do with the rest of the bozos
   RewriteRule ^(.*)$ - [R=403,L]
</IfModule>

And with these, most of the annoying log entries probing your WP install should leave your site frustrated.

Weird times mean New Rules – UFW

I added many new UFW rules and other security measures to my Ubuntu server as a result of all the weird things happening in Europe right now. There was a time when I would have done this immediately after building the server, but I have been getting lax in my old age

I also added a number of DENY rules to stop HTTP site scanning. I haven’t had to block a /8 yet, but there are a few /16 and /15 networks in my deny list. This with some well-placed .htaccess rules made many annoying bots go away.

In my research, I have found that there is a desire to completely block entire countries (you know who you are). Doing so with CIDR-based firewall rules is intensive – the UFW ruleset for one of the countries had 24,000+ CIDR blocks!

If you are running home servers, I highly recommend blocking SSH from as much of the internet as possible. As well, keep up-to-date with security patches and block all the stupid ways people can use your servers.

And make sure your cable router/device in front of your network is blocking everything except the most important stuff.

New Server – New Fun!

This is the amazing “new” server that this blog is hosted on. Using a dynamic DNS service and Ubuntu on a 9 year-old MacBook, I have taken control of my blog again, trying to revive it from the untouched archive it has been for the last few years.
[Oh, and if you have arrived here from a Newest Industry link, don’t panic. Just search for the article you want – they’re all here.]

I’ve just recently changed companies (through an acquisition), so I will have new web performance items to hook into as I get a chance to work with new customers.
All raise your glass – PerformanceZen is back.

Performance Trends for ???? – Smarter Systems

IF-repair by Yo Mostro (Flickr)

Most of the trending items that I have discussed in the last two weeks are things that can be done today, problems that we are aware of and know need to be resolved. One item on my trend list, the appearance of smarter performance measurement systems, is something the WPO industry may have to wait a few years to appear.

A smarter performance measurement system is one that can learn what, when, and from where items need to be monitored by analyzing the behavior of your customers/employees and your systems. A hypothetical scenario of a smarter performance measurement system at work would be in the connection between RUM and synthetic monitoring. All of the professionals in WPO claim that these must be used together, but the actual configuration relies on humans to deliver the advantages that come from these systems. If RUM/analytics know where your customers are, what they do, and when they do it, then why can’t these same systems deploy (maybe even create and deploy!) synthetic tests to those regions automatically to capture detailed diagnostic data?

Why do measurement systems rely on us to manually configure the defaults for measurements? Why can’t we take a survey when we start with a system (and then every month or so after that) that helps the system determine the what/when/where/why/how of data and information we are looking to collect and have the system create a set of test deployment defaults and information displays that match our requirements?

The list of questions goes on, but they don’t have to. Measurement systems have, for too long, been built to rely on expert humans to configure and interpret results. Now we have a chance to step back and ask “If we built a performance measurement system for the a non-expert, what would it look like?”

More data isn’t the goal of performance measurement systems – more information is what we want.

Performance Trends 2013 – Employees are Customers too

Peter Levine from Andreesen Horowitz wrote an article on The Renaissance of Enterprise Computing yesterday that finally sprouted the seed of an idea that has been dormant at the back of my brain for a few months. While the ideas of enterprise computing and web/mobile performance seem disconnected, they’re not.

When companies begin to rely on outside services (Levine mentions Box, Google Docs, and others in his article) they have given part of their infrastructure over to an outside organization. And, when you do that, this means that any performance hiccups that affect us as consumers can have a very major effect on us as employees.

Even if your company decides to purchase and deploy an enterprise application within your own infrastructure or datacenters, the performance and experience that your employees experience when using it on their desktops or on their mobile devices can affect productivity and effectiveness in the workplace. An unmanaged (read unmonitored) solution can have shut down groups in the company for minutes or hours.

Think of the call-center. No matter the industry you’re in, what increase customer calls: slow performance or a poor experience with the web/mobile application. Now, if your employees rely on a variant of the same web application to answer questions in the call-center, have you actually improved the customer experience and increased employee productivity?

Some considerations when managing, designing, or buying an enterprise application in the coming  year:

  • What do your peers tell you about their experience implementing the solution or using an outside service – has it made employees more effective and efficient?
  • Are employees already using a “workaround” that makes them more effective and efficient? Why aren’t they using the internal or mandated solution?
  • Is performance and experience a driving factor in the lack of adoption of the mandated solution?
  • Do you have clear and insightful performance information that shows when employees are experiencing issues performing critical tasks? Can you clearly understand what the root cause is?
  • Are employees experiencing issues using the application in certain browsers or on certain mobile devices? How quickly can your design or your outside service respond to these issues?
  • Are you reviewing the chosen solution regularly to understand how usage is changing and how this could affect the performance of the application in the future?

Performance issues are not simply affecting the customers you serve. Your own employees use many of the same systems and applications in their day-to-day tasks, so a primary goal of managing these application should be to ensure that the applications deliver performance and experience that encourages employees to use them, no matter whether they are developed in-house or purchased as software or SaaS.

Web Performance Trends 2013 – Third Party Services

Every site has them. Whether they’re for analytics, advertising, customer support, or CDN services, third-party services are here to stay. However, for 2013, I believe that these services will face a level of scrutiny that many have avoided up until now.

Recent performance trends indicate that while web site content has been tested and scaled to meet even the highest levels of traffic, the third-party services that these sites have some to rely on (with a few exceptions) are not yet prepared to handle the largest volumes of traffic that occur when many of their customers experience a peak on the same day.

In 2013, I see web site owners asking their third-party service providers to provide verification that their systems be able to handle the highest volumes of traffic on their busiest days, with an additional amount of overhead – I suggest 20% – available for growth and to absorb “super-spikes”. Customer experience is built on the performance of the entire site, so leaving a one component of site delivery untested (and definitely unmonitored!) leaves companies exposed to brand and reputation degradation as well as performance degradation.

In your own organizations, make 2013 the year you:

  • Implement tight controls over how outside content is deployed and managed
  • Implement tight change control policies that clearly describe the process for adding third-party content to your site, including the measurement of performance impacts
  • Define clear SLAs and SLOs for your third-party content providers, including the performance levels at which their content will be disabled or removed from the site.

When speak to your third-party content and service providers about their plans for 2013, ask them to:

  • Explicitly detail how they handled traffic on their busiest days in 2012, and what they plan to do to effectively handle growth in 2013
  • Clearly demonstrate how they are invested in helping their customers deliver successful mobile sites and apps in 2013
  • Lay out how they will provide more transparent access to system performance metrics and what the goals of their performance strategy for 2013 are.

Take control of your third-party content. Don’t let it control you.

Web Performance Trends for 2013 – Performance Optimization

As we approach the end of 2012, I will be looking at a few trends that will become important in 2013. In a previous post, I identified optimization as an important performance trend to watch. It is one of the items on a performance checklist that companies can directly influence through the design and implementation of their web and mobile sites.

The key to optimization in any organization is to think of objects transmitted to customers, regardless of where they originate, as having a cost to you and to the customer. So, a site that makes $100,000 in a day and transfers 10 million objects to customers has an object-to-revenue ratio of 100. But, if the site is optimized and only 7.5 million objects are transferred to make $100,000, that ratio goes down to 75; and if the reduction in objects causes revenue go up to $150,000, the ratio drops to 50.

This approach is simplistic and does not include the actual cost to deliver each object, which includes costs for bandwidth, CDN services, customer service providers, etc. as well as revenue generated by third-party ads and services you present to customers. The act of balancing the cost of the site (to develop and manage), the performance you measure, the revenue you generate, the experience your customers have, and the reputation of your brand is an ongoing process that must be closely considered every time someone asks, “And if we add this to the site/app…”.

There is no optimal figure for site optimization. But there are some simple rules:

  • Use Sprites where you can. Combing multiple small images into aggregated image maps that you can use CSS to display gives you a double-plus good improvement – fewer objects to download and more text (HTML, JavaScript, and CSS) that can be delivered to visitors in a compressed format
  • Combine JavaScript and CSS files. Listen to your designers – they will likely try to convince that each file needs to be separate for some arcane reason. Listen and then ask if this is the most efficient way to deploy this particular function or formatting. Ask the developer to produce a cost/benefit analysis of doing it their way versus using something that is already in place
  • Control your third-party services. This means having a sane method for managing these services, and shutting them off if necessary. Have every team that is responsible for the site meet to approve (or deny) the addition of new third-party services. And those who want it better come with a strong cost/benefit analysis.

Optimization is the act of making the sites you create as effective and efficient as the business you run. No matter how “low” the cost to operate a web site is, each object on a site can cost the company more money than it is worth in revenue. And if that object slows the site down, it could turn a profitable transaction into a lost customer.

Web Performance – At What Cost? Trends for 2013

image courtesy of Corey Seeman – http://www.flickr.com/photos/cseeman/

As we moved through the traditional start of the holiday shopping season (Thanksgiving / Black Friday / Cyber Monday), it is clear that most sites were prepared for what was coming. No big names went down, no performance slowdowns rose to the headlines, and online revenue – both web and mobile – appears to have increased over 2011.

But when you these companies do their year-end review, they need to take a step back and ask: “Could we have done it better?”

While performance events were few and far between (if they occurred at all), companies will need to examine the cost of scaling their sites for performance. When planning for the peak performance period, companies will need to asses whether simply scaling-up to handle increased traffic and sales could have been managed more effectively, by implementing sites that were not only fast, but  also efficient.

Joshua Bixby (here) noted that web page size has increased 20% in the last 6 months, an indication that efficiency is not always at the top of mind when new web content is presented to visitors. In order to deliver ever more complex web content, companies are spending more on services such as CDNs and cloud services to deliver their own content, while incorporating ever increasing numbers of third-party items into their pages to supply additional content and services (analytics, performance, customer service, Help Desk, and many more) that they have outsourced.

Increasing page size, outside acceleration and cloud services, and third-party services – a potent mix that companies need to asses critically, with an eye to understanding what all of these mean for the performance experienced by their visitors and customers. Add in the increasing importance of the mobile internet, with its variable connection speeds and service quality, and things become even more interesting.

In 2013, I see companies assessing these three trends with a focus on making sites perform the same (or better!) at the same (or lower!) cost than they did in 2012.
Over the next 12 months, I will be watching the performance industry news to see if those companies that have been successful at making their sites perform under the heaviest loads increasingly focus not just on speed and availability, but on efficient delivery of their entire site at a lower cost with the best user experience possible.

The key strategics questions that online businesses will be asking in 2013 will be:

  • Have we optimized our content? This does not mean make it faster, this means make it better and more efficient. It is almost absurdly easy to make a big, inefficient site fast, but it is harder to step back and “edit” the site in a way that you deliver the same content with less work – think Chevy Volt, not Cadillac Escalade.
  • Are we in control of our third-party services? Managing what services get placed on your site is only the first step. Understanding where the content you have added comes from and whether it is optimized for the heaviest shared loads will also become important checklist items for companies.
  • Can we deliver the design and functionality our customers want at a lower cost? This is the hardest one to be successful at, as each company is different. But Devops teams should be prepared to be accountable for not just cool, but also for the cost of creating, deploying, and managing a site.

Managing Performance Measurement: Who uses this stuff anyway?

One of the least glamorous parts of managing performance measurement data is the time I have to take every month to wade through my measurements and decide which stay on and which get shut off. Since I’m the only person who uses my measurement account, this process usually takes less than 10 minutes, but can take longer if I’ve ignored it for too long.

With large organizations that are collecting data on multiple platforms, this process may be more involved. By the time you look at the account, the tests have likely accumulated for months and years, collecting data that no one looks at or cares about. They remain active only because no one owns the test and can ask to disable it.

What can you do to prevent this? Adding some measurement management tasks to your calendar will help prevent Performance Cruft from clogging your information pipes.

  1. Define who can create measurements. When you examine account permissions on your measurement systems, do you find that far more people than are necessary (YMMV on this number) have measurement creation privileges? If so, why? If someone should not have the ability to create new measurements, then take the permissions away. Defining a measurement change policy that spells out how measurements get added will help you reduce the amount of cruft in your measurement system.
  2. Create no measurement without an owner. This one is relatively easy – no new measurement gets added to or maintained on any measurement system without having one or more names attached to it. Making people take responsibility for the data being collected helps you with future validations and, if your system is set up this way, with assigning measurement cost to specific team budgets. It’s likely that management will make this doubly enforceable by assigning the cost of any measurement that has no owner to the performance team.
  3. Set measurement expiry dates. If a measurement will be absolutely critical during  only a specific time range, then only run the measurement for that time. There is no sense collecting data for any longer than is necessary as you have likely either stored or saved the data you need from that time for future analysis or comparisons.
  4. Validate measurement usage monthly or quarterly. Once names have been associated to measurements, the next step is to meet with all of the stakeholders monthly or quarterly to ensure that the measurements are still meaningful to their owners. Without a program of continuous follow-through, it will take little time for the system to get clogged again.
  5. Cull aggressively. If a measurement has no owner or is no longer meaningful to its owners, disable it immediately. Keep the data, but stop the collection. If it has no value to the organization, no one will miss it. If stopping the data leads to much screaming and yelling, assign the measurement to those people and reactivate.

Managing data collection is not the sexiest part of the web performance world, but admitting you have a data collection cruft problem is the first step along the path of effective measurement management.

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