The moment a PHP application grows to run on more servers, normally people will see problems caused by PHP sessions. If the application is not persistent you are lucky and don’t care about this, but if not you will quickly see this regardless of how good the load balancer you use is handling stickiness (sending the users to the same real server), this will slowly become a major issue. There are various solutions that can be used to store PHP sessions in a shared location, but I want to present today one solution that is very simple to implement, yet very efficient and on the long term better suited than using a database backend for this: using memcache to store the sessions.

The pecl memcache php extension has supported for a long time the memcache session.save_handler, but with the release 3.0.x (still in beta at this time) this brings in a set of interesting features for us:
- UDP support
- Binary protocol support
- Non-blocking IO using select()
- Key and session redundancy (values are written to N mirrors)
- Improved error reporting and failover handling

Read the rest of this entry »

If you are trying to compile php with the option –with-interbase and receive this error:
configure: error: libgds, libib_util or libfbclient not found
it means that you don’t have firebird development libraries installed.

If you are running on debian you can easily install firebird development libraries using:
aptitude install firebird2-dev
and you should be able to move forward with the compile.

If you have seen an error like “Fatal Error: PHP Allowed Memory Size Exhausted” in apache logs or in your browser, this means that PHP has exhausted the maximum memory limit. This post will show 3 different ways on how you can increase the php memory limit and also explain when you should use them.

First, let’s see where is this limit coming from. Normally you will see from the error message what is the actual limit, as this will look like:
PHP Fatal error: Allowed memory size of X bytes exhausted (tried to allocate Y) in whatever.php
The default value might differ depending on what php version and linux distribution you are running, but normally this will be set to either 8M or 16M. For example on my debian etch, running on php 5.2 this is set by default at 16M.

In order to identify the current value on your system, look inside your php.ini and search for memory_limit:
memory_limit = 16M ; Maximum amount of memory a script may consume (16MB)

There are three ways to change this value, the obvious way – changing the global value from php.ini, but also an individual method to change it just for a script, or folder. Read the rest of this entry »

After a long time being supported only as beta (and this by CPanel meaning no support at all), CPanel is finally offering full support for PHP5 on all its latest versions – 10.8.2 – (Stable/Release/Current). I have been using PHP5 on some CPanel servers for a long time without any problems, but now probably they will push towards making this the default choice. Still PHP 4.4.2 is the default version that CPanel will install, but I assume that this will change soon. So it might be a good idea to try to upgrade to PHP5 (or start updating your applications to work on PHP5 as this will soon be needed).

We can choose from various versions of PHP5: 5.0.4, 5.0.5, 5.1.2, 5.1.4… Hmm I feel that they could have added some more . My choice was (as I assume most of the peoples will do) the latest version available PHP 5.1.4… Anyway I have not seen any problems on the servers I am using php5 (centos/rhel) besides some application incompatibilities that are being worked on by the developers.

To upgrade your CPanel to PHP5 just use the regular buildapache method. For more details you can see my previous post: “Upgrade php on CPanel/WHM”.