Dec 24 2015

WordPress core dump files

Core dump files WordPressA couple of weeks after I launched a new blog, I noticed four ‘core’ files named core.2801, core.4065 etc. in its directories. The files seemed harmless, but had rather large size (several megabytes).

What are core dump files?

A quick Google search turned up a lot of complicated pages explaining the problem, but none that could actually suggest a fix.

A web developer suggested that the core files were a result of lots of buffer being dumped. This is typical of excessive resource usage and/or error reporting. Core dumps contain reports of working memory of a software when it has crashed. In short, core dump files are caused by a crashing software component. Instead of trying to get rid of core files, you should worry about what caused these errors.

You can safely delete these files. Although there is GDB to open and analyze core files, not many would actually understand anything. WordPress is tested thoroughly before each release, hence it is unlikely a fault caused by WP.

Prevent core dump files

You can delete core files without any worry – it does not contain data useful to anyone but developers and hosting company itself.

Incompatibilities arising out of Apache, MySQL, PHP etc could cause core dumps. Google version number of these software along with the terms “incompatibility WordPress”.

If possible, use only plugins written by experienced developers. New developers may not adhere to the best coding practices. A poorly coded plugin could cause core dumps.

Upgrade WordPress plugins to the latest version. Regarding the problem on the new blog, I found that I had uploaded a older versions of a couple of plugins.

Disable plugins. You can start out by disabling all the heavy plugins and enabling them one by one, during which time you should watch blog directory, wp-admin etc. for core files. If a plugin does not trigger core files, activate another and test. Repeat the process until all plugins have been activated or the culprit has been found.

The core dumps could also have been due to WP. The most usual cause of a core dump is because of running out of memory on your server – if you’re on a shared host, ask to be moved to a different node. If you’re on a VPS/Dedicated Server, up your memory a little and the problem should stop.
Plugins that send large amounts of data may also cause this.  For example, some idiots keep trying to brute force my admin login and I had it set to send an email on all failed logins.  I had to install a new plugin because it was sending out so many emails it hit the max limit on my hosting service.  The new plugin restricted the login attempts to 5 and then blocks them after that.  This solved my problem, I just had to go delete all the .core files dumped into my folder.