httpd: accelerate web page performance with mod_expires

More and more goodies are packaged with apache2, allowing one to perform front-end engineering right out of the box. Here are a tip on using mod_expires to maximize the use of browser cache and accelerate performance for repeat visitors. (more…)

Making the case for a virtualized hardware appliance

As Data Center infrastructures become more virtualized, the desire for virtualized network services increases. We see 2 types of offerings:

1. virtual appliances delivered in a VM image, such as the Netscaler VPX from Citrix
2. hardware appliances that can be virtualized, such as Cisco ACE or ASA

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Sizing Concurrent Users & Connections in a Web Environment

Calculating concurrent connections for new web applications isn’t an exact science. Fortunately Sun published a guide with an overview of the sizing process that can be applied to most web applications. (more…)

Google Tech Talk – A look at Web Security

This is a bit dated (April ‘06) but still very much relevant. This video is a tech talk delivered at Google by security expert Mike Andrews. n this TechTalk, Mike Andrews examines how web applications are attacked, walk through a testing framework for evaluating the security of an application and take some deep-dives into a few interesting and common vulnerabilities and how they can be exploited. A good primer for folks interested in Web App Firewalsl.

clustering versus load-balancing

Seems that often times the concept of clustering is often mixed up with that of load-balancing. I thought I’d quickly write something up to help clarify the difference between the two.

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when web people think architecture

I don’t recall when or how I found highscalability.com but it’s one of the sites that I bookmark and review periodically. Finally, a website that caters to us application/server folks that need to know what it takes to build an environment that support gazillion users. (more…)

local & global load balancing on the cheap

Not many people know what LVS is. I ran World Health Organization’s public website (www.who.int) using a pair of Compaq DL360 servers running Linux Virtual Server, which is an open-source load-balancer. And guess what, during SARS, we saw over 14 million hits a day at the peak. While I don’t have the specific cps / concurrent conn numbers (we didn’t measure those), the boxes did just fine. (more…)

tuning apache and a different perspective on web app performance

Here’s another article that I can really relate to. Typically a standard install of Apache has lots of extra (often unused) features and won’t take full advantage of all system resources. There are all sorts of things you can do (like recompiling to support more concurrent connections, which is what I’ve had to do). (more…)