This blog will be moving to a new server very soon. If all goes well, you shouldn’t notice a thing. But just in case, I figured I’d give a warning, so that if you try to visit and you get an error, or the site won’t come up, you’ll know to just come back again later instead of thinking that my site was an early victim of the 2012 apocalypse or something.

I’m doing more than just moving onto a new server though. I’m moving to a new hosting provider, and I’m reconfiguring many aspects of how my services are set up. If you’re interested in the technical nitty-gritty, read on.

Some of you might recall that a little over a year ago, I moved from my original hosting onto Slicehost. I am now moving again, to a service called prgmr.com. I’ve had no problems with Slicehost, but the pricing for prgmr.com is lower, which made it possible for me to expand from 2 servers to 4 servers for less money.

Slicehost VPS hosting is pretty no-frills. You get a server with an initial OS installed on it, and a web-based management tool with some DNS tools and a Java applet console. With prgmr.com, it’s even more no-frills, because the console isn’t web-based. It’s SSH all the way, baby. It’s not for everybody, but it suits me fine. And even though I have more servers, it reduces my monthly hosting costs by about 40%. That said, I’m also reducing my virtual CPU power and disk space a little bit, and Slicehost has multiple facility locations, which might be factors for someone else shopping for hosting. For me, the ability to afford more servers was pretty high up.

So, that said, let’s look at what I’m changing in my setup, and why I felt it was important to move up to 4 servers.

All along, even before Slicehost, I have had trouble dealing with traffic spikes on my web server. I’ve used WP Super Cache and W3 Total Cache. I’ve used XCache for PHP code caching, and for my WordPress object cache. I’ve configured Apache to set caching headers for static files using mod_expires to reduce requests. But I still get load and memory spikes that grind my server into dust. That shouldn’t happen with only 200 visitors per hour (granted, a page view can generate about 50 HTTP requests). Obviously, I’ve configured my server poorly.

Like many large PHP applications, WordPress can be a bit hungry for memory. So when it fights against MySQL and an in-memory object cache for resources, things can start to get dicey. And of course, I’ve got a few other things on the server. When I get hit by a traffic spike (popular article, spammer runs, errant search spiders, etc), memory goes away fast. The machine starts to swap, things get slow, load average spikes as processes begin to wait for resources, and it all snowballs. I’ve got some homemade scripts that keep an eye on things and attempt to restart various services in order to force things back into line, but it’s a pretty heavy-handed way to deal with the problem.

In my new setup, here’s what I’m doing to fix it:

• I’ll be running Apache, MySQL, and Memcached all on separate servers, instead of together on one host.
• I’m switching from the Apache pre-forking model to the threaded worker model.
• I’m switching from mod_php to FastCGI (mod_fcgid) and php-cgi.

There will probably be other tweaks, as well, but those are the biggies. I’m expecting this new setup to handle waaaay more requests than the old one. Oh, and I’m definitely open to any pointers from performance tuning gurus. Please share links and tips!

When the switch-over happens, there might be a period of transition while the DNS changes propagate. I don’t plan to post again until I’ve moved this blog fully to the new host. So you’ll know it’s happened when a new article appears here.

Related posts:

1. Roadwork Next 15 Miles
2. Now on Slicehost: Me!
3. W3 Total Cache Plugin

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Simple two column theme with shades of blue that you can use to customize your site

Martial Arts Lover

A nice, clean, dark and simple wordpress theme with one right sidebar.

5 Girl-Inspired Free WordPress Themes

Set of five two column, widget ready themes

WP Commerce Flex

It features a variety of options, solid SEO-friendly CSS layout that is easily customizable, and built for seamless integration with PHPbay and PHPZon.

Polka Dots

It’s widget-ready, adsense-ready, and 3-columns.  Colors: brown, white, aqua, green, chartreuse, yellow, orange, red.

I’m going to be on the WordPress Weekly podcast next Tuesday (dialing in from the Bay Area, hopefully will find a spot for the interview that will work OK). There is a thread at WP Tavern for people to post questions they’d like to hear me discuss.

I think there are a lot of very interesting things to cover about the new affiliate program from the WordPress HelpCenter, monetization and supporting the WordPress development community. So far it looks like some folks would like to hear about Carrington as well – I’ll be happy to try cover that as well.

Feel free to post questions in the comments here if you like and I’ll pass them along.

If you’re looking for a cool way to keep tabs on what’s shaking at WordCamp New York this weekend, check out this site created by DimensionMedia called IWishIWasAtWordCamp.com. The site contains feeds from a few notable Twitter accounts that will be tweeting during the event as well as the important hashtag Twitter widget which goes above and beyond single accounts. Near the center of the site is a collection of photos published to Flickr but some of the photos are from the wrong WordCamp. This should be fixed by only aggregating photos that are using a unique tag such as the event Twitter hashtag. Near the bottom are even more Twitter accounts. The only bad thing about this page is that asides from the hashtag widget at the top, the rest of the page requires refreshing in order to see new information. Hopefully, Dimension has a decent server to put up with the load but I would have used the cool new Twitter widgets to see updates as they happen.

If you have any feedback, let him know in the comments!

2.8.6 fixes two security problems that can be exploited by registered, logged in users who have posting privileges.  If you have untrusted authors on your blog, upgrading to 2.8.6 is recommended.

The first problem is an XSS vulnerability in Press This discovered by Benjamin Flesch.  The second problem, discovered by Dawid Golunski, is an issue with sanitizing uploaded file names that can be exploited in certain Apache configurations. Thanks to Benjamin and Dawid for finding and reporting these.

Get WordPress 2.8.6.

This weekend will be packed with WordCamp goodness starting with WordCamp Phoenix on Friday the 13th and WordCamp New York on Saturday the 14th as well as Sunday the 15th, both of which still have tickets available. However, if you can not make it to WordCamp Phoenix, the great news is that it will be live video streamed in its entirety thanks to their sponsorship with GoDaddy. Simply point your browsers to their Live Video page and the event will be streamed starting at 9AM Mountain time. Also check out the schedule of events in case you only want to tune in during a certain session.

Because of a lack of WiFi and bandwidth at WordCamp New York, there will be no live audio or video streams.

*UPDATE* Just found out that WordCamp Victoria in Canada is also this weekend.