in this article we get a sense of lamp performance on ec2 by running a series of benchmarks on the drupal cms system. these benchmarks establish read throughput numbers for logged-in and logged-out users, for each of amazon's hardware classes.
we also look at op-code caching, and gauge it's performance benefit in cpu-bound lamp deployments.
the previous article showed you how to set up jmeter and create a basic test. to produce a more realistic test you should simulate "real world" use of your site. this typically involves simulating logged-in and logged-out users browsing and creating content. jmeter has some great functionality to help you do this.
when making scalability modifications to your system, it's important to quantify their effect, since some changes may have no effect or even decrease your scalability. the value of advertised scalability techniques often depends greatly on your particular application and network infrastructure, sometimes creating additional complexity with little benefit.
apache jmeter is a great tool to simulate load on your system and measure performance under that load. in this article, i demonstrate how to setup a testing environment, create a simple test and evaluate the results.
it is often important for system administrators to get real time notification of critical events. unfortunately, it isn't immediately obvious how to do this in the syslog framework. in this article i show you step-by-step how to do this.
one of the biggest problems is the lack of constants. how many times have you wanted to code something like this?
light_grey = #CCC. instead you are forced to repeat
#CCC in your css. this quickly creates difficult-to-maintain and difficult-to-read code.
clearly guardians shouldn't be used as a crutch for a badly configured system. used appropriately, however, they can decrease downtime due to unexpected events or administrator-error.
in this article, i describe how to implement, install and configure a guardian using a lightweight bash script. i go on to describe how to watch over your lamp install using this guardian. please note that all code and configurations have been tested on debian etch but should be useful for other *nix flavors with subtle modifications.
the blessing and curse of cck is the ability to quickly create very complex node types within drupal. it doesn't take very long before the input form for a complex node type has become unmanageably long, requiring your user to do a lot of scrolling to get to the bottom of the form. the obvious solution is to break your form into multiple pages, but there is no easy way to do this. there do exist two proposed solutions to this, the cck wizard module and a drupal handbook entry. however, the well-intentioned cck wizard module doesn't seem to work, and the example code in the drupal handbook becomes tedious to repeat for each content type. to fill the void, i bring you cck witch
cck witch is based on the same premise as the handbook entry : the most natural way to divide a cck form into pages is to use field groups. from there, however, cck witch diverges, taking a relatively lazy, yet effective approach to the problem of multi page forms: on every page we render the entire form, but then simply hide the fields and errors that do not belong to the current step. it also offers an additional feature : when the form is complete and the node is rendered, an individual edit link is provided for each step - allowing the user to update the information only for a particular page in the form, without having to step through the entire wizard again.
if you've now read enough to be curious to see the goods, then please, be my guest and skip straight to the live demo.
your treasured pictures, videos and documents may still be at risk. your computer could be stolen, destroyed by flood or fire or chopped into small pieces by a jealous ex-lover.
using a remote backup service is a good way to mitigate against this type of problem. for around $10 a month, you can find companies willing to store 10Gb of data for you. your data is usually accessible using a variety of methods, including
ftp. to see some of these services, type remote backup rsync service into google.
in this article, i discuss using open source software to take advantage of these services in an efficient and secure manner, allowing the backup of large directories over a dsl-speed line while you sleep.
using the term "content management system" to describe the drupal cms understates it's full potential. i prefer to consider drupal a web-application development-system, particularly suitable for content-heavy projects.
what are the fantastic four?
drupal's application development potential is provided in large-part by a set of "core" modules that dovetail to provide an application platform that other modules and applications build on. these modules have become a de-facto standard: drupal's fantastic four. our superheros are cck, views, panels and cck field types and widgets. if you are considering using drupal to build a website of any sophistication, you can't overlook these.
if you've setup a clustered drupal deployment (see scaling drupal step three - using heartbeat to implement a redundant load balancer), a good next-step, is to scale your database tier.
in this article i discuss scaling the database tier up and out. i compare database optimization and different database clustering techniques. i go on to explore the idea of database segmentation as a possibility for moderate drupal scaling. as usual, my examples are for apache2, mysql5 and drupal5 on debian etch. see the scalability overview for related articles.