Tag1 Consulting is focused on improving Drupal's performance and scalability. We also believe that when information is freely shared, everyone wins. Toward these ends, we are working on an online book titled, "Drupal Performance and Scalability". The book is divided into five main sections, Drupal Performance, Front End Performance, Improved Caching and Searching, Optimizing the Database Layer, and Drupal In The Cloud. The book is primarily aimed toward users running Drupal on the LAMP stack, with chapters applicable to everything from low-end shared hosts to large-scale multi-server installations.

By publishing on-line, we aim to encourage you to participate in the book writing process as an editor and a technical reviewer. You will currently find the book's complete outline online, along with descriptions of each planned section and chapter. As the book evolves, it will continue to be updated online in real time. We encourage you to post comments with suggestions, critical feedback, grammatical corrections, or anything else relevant to our ongoing effort.

The second of the two-part Scalable Linux Clusters article. This second part features the addition of Heartbeat and ldirectord to the network started in Part I.

Continuing my plans to set up an IPVS high-availability LAMP stack on EC2, I needed to add the kernel modules for IPVS. I have been using the CentOS machine images provided by RightScale, which have unneeded services disabled and, although they are set up to work with RightScale's software, work very well for general use. Unfortunately, the IPVS kernel modules are not among those pre-installed on the AMI.

This last week I've had the fortune to have some spare time to play around with Amazon's Elastic Compute Cloud (EC2). I'm pretty interested in the potential for scaling the LAMP stack by having a programmable cluster at the service of your box.

With all the excitement surrounding cloud computing, and specifically Amazon's EC2 (Elastic Compute Cloud) Beta service, I decided it was time to give it a try myself. Without much personal background in the new service, I found that there are an overwhelming number of pages talking about EC2, and even Drupal on EC2, but didn't locate a simple guide to quickly get me up and running. Having now spent a few hours today learning the basics, I'm jotting down these quick notes to help the next person interested in trying the same, and in the hopes of attracting useful tips from other AWS users.

Whether you are perusing mailing lists or reading the large LVS-HOWTO, much of the available information on creating a high-availability Linux cluster can be difficult to sift through. Relevant information shares space with implementation details dating back to version 2.0 of the Linux kernel and comments that are often ambiguous at best.

This two-part article attempts to present an up-to-date tutorial on setting up LVS for your network, with an emphasis on designing a system that matches your infrastructure’s needs.