It’s not what you look at that matters, it’s what you see. — H.D. Thoreau

Most performance conversations, at one point or another, will get to the subject of caching. And for a good reason. Caching helps to hide some of the biggest performance inefficiency in many systems. That’s right, hide not fix. Whether it’s local storage of data, pre-calculated data set or a transient storage to reduce a number of server-side requests, all these methods are improving performance by limiting the frequency of expensive operations. …

Books

DevOps and Business — O’Reilly Media

Interviews and Quotes

DevOps & Business— DevOps Дефлопе podcast (Russian)
Importance of culture — Gun.io podcast
Business Monitoring — DevOps Дефлопе podcast (Russian)
Citizen developers push the pace in BizDevOps — TechTarget
AWS appeals to the masses with low-code development project — TechTarget
Evolution of DevOps — O’Reilly
Wondering what comes after DevOps? …

Unless you are running a complete brochureware site, chance are, you have some sort of content personalization requirement, whether it’s user’s name, number of items in the shopping cart, custom navigation or something entirely different, specific to a particular user.

Let’s examine a prototype of a standard e-commerce personalization logic.

When a user logs in, on success, we store their identifier in a session variable (commonly — browser cookie). When that user navigates to a different page, we retrieve user information (to acquire first name to display) based on the identifier stored in a local cookie and then, if the user exists, we pull user’s shopping cart information to display a number and, in this case, amount of items in the cart. …

In this day and age, more and more applications leverage external services. So much so, that only about 6% of all sites has no 3rd party content and almost 40% of all site have between 75% and 99% 3rd party content. And for a good reason. External services provide a tremendous benefit, not only in brand familiarity and content, but also in cost saving, considering you’re leveraging years of someone else’s work for your gain.

However, one of the major risks when implementing a third party service is the reliance on the availability of that third party service. Availability of your production site. Based on the service that you have no control over. And no matter how large or successful the service that you’re using is — it will go down (or become unavailable) at one point or another. Perhaps the best example of it is using Google CDN for jQuery, only to realize that your site will break for all Chinese users, since, you know, China blocks all traffic coming from Google. …

I gave a talk at DevOpsDays Baltimore about biases that influence our daily decisions.

Bias in tech from Leon Fayer

Every day we make decisions. Those decisions can be around improving your product, process, company; sometimes even bettering yourself. But many of our decisions are not made consciously. We all have biases. And even though most of our biases are unconscious, those biases still can get in a way of making the best possible decision. This is not a talk about gender and racial bias in tech hiring. This is a talk about different biases that skew our technical decision process that we deal with in out day-to-day operations.

Every type of content was not created equal. Nor should it be served the same way. At a high level, you can separate your content into 3 groups:

• infinitely static — image is a perfect example of this. Once an image has been published, you should never update it (because multiple reasons) and should be able to cache it almost indefinitely.
• temporarily static — this covers the content that renders into static output. CSS, articles, etc. …

Loops are generally not great from the performance perspective, but often times it’s relatively easy to pinpoint and optimize those inefficient function you wrote and call inside of a loop. But sometimes, especially with JavaScript, the functions causing the performance hit are the ones that are provided to you by language.

Let’s look at the most basic example of taking an array of items and adding them to your html table.

for (var i = 0; i < items.length; i++) {
  document.getElementById("listGrid").innerHTML += "<tr><td>" + 
                                                   items[i].name + 
                                                   "</td></tr>";
}

This is pretty straight forward. Iterate through the array and inject each item name into a listGrid table . There are no special functions to worry about, this loop is based purely on JavaScript-provided functions for doing exactly those things. …

Perhaps the most effective caching mechanism is in-memory cache. Tools like memcached and redis give a great out-of-the-box capability to store and retrieve your content to/from memory and effectively manage TTL. But what can you do when you don’t have those tools available?

Never fear, you can implement your own on-disk cache. While not as effective as in-memory cache, it would still provide a significant relief to system under heavy load.

The basics

The premise is simple. …