tech
lamp on amazon ec2 shaping up nicely
posted april 14th, 2008 by john
recently i posted some encouraging performance benchmarks for drupal running on a variety of servers in amazon's elastic compute cloud. while the performance was encouraging, the suitability of this environment for running lamp stacks was not. ec2 had some fundamental issues including a lack of static ip addresses and no viable persistent storage mechanism.
amazon are quickly rectifying these problems, and recently announced elasic ip addresses; a "static" ip address that you own and can dynamically point at any of your instances.
today amazon indicated that persistent storage will soon be available.
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backing up your xen domains
posted february 10th, 2008 by john
backups are boring, but we all know how important they are. backups can also be quite powerful when working with xen virtualization, since xen allows for convenient back-up and restore of entire systems.
i've recently been working on a flexible, general-purpose script enabling incremental backups of complete xen guests, optimized for secure, distributed environments; xenBackup. if you're working with xen, you might find it useful.
the xenBackup script leverages open-source components like ssh, rsync, and rdiff-backup to create a simple, efficient and functional solution.
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lamp performance on the elastic compute cloud: benchmarking drupal on amazon ec2
posted january 28th, 2008 by john
amazon's elastic compute cloud, "ec2", provides a flexible and scalable hosting option for applications. while ec2 is not inherently suited for running application stacks with relational databases such as lamp, it does provide many advantages over traditional hosting solutions.
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.
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load test your drupal application scalability with apache jmeter: part two
posted january 18th, 2008 by john
i recently posted an introductory article on using jmeter to load test your drupal application. if you've read this article and are curious about how to build a more sophisticated test that mimics realistic load on your site, read on.
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.
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load test your drupal application scalability with apache jmeter
posted january 13th, 2008 by john
there are many things that you can do to improve your drupal application's scalability, some of which we discussed in the recent scaling drupal - an open-source infrastructure for high-traffic drupal sites article.
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.
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how to setup real-time email-notification for critical syslog events
posted december 20th, 2007 by johnit 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.
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supercharge your css code with m4
posted december 19th, 2007 by johnone 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.
an elegant solution to the problem is to use a general purpose preprocessor like m4. m4 gives you a full range of preprocessing capability, from simple constants to sophisticated macros.
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using a guardian to ensure your lamp site is always up
posted december 18th, 2007 by john
to guarantee maximum uptime for your site, it's a good idea to periodically check the health of your system and restart failing components. you can use a simple program to do this automatically. i like to call this type of program, a "guardian".
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.
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cck witch - multi-page cck forms for drupal
posted december 11th, 2007 by cailin
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.
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never lose your data again: backup remotely using rsync ssh and rdiff-backup
posted december 5th, 2007 by john
if you've ever lost precious data after a hard drive failure, you've probably learned your lesson and are now automatically backing up your system.
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 rsync, vpn and 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.
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