Huge Core Dump Files in WordPress Folders

By 26-03-2009   BloggingDomain HostingSite NewsWordPress

What are core dump files, and what do they signify in WordPress folders? I was surprised to see my WordPress folder sizes increasing and FTP revealed huge ‘Core’ dump files in several folders of my WordPress installation. As they gobbled up my server storage space, I had no idea where these came from and what to do with them.

WordPress core dump files

I found this 38MB core file in the root directory of my WordPress installation

core file

As I looked in subfolders, I found another 46MB core file in wp-admin

core dump

As you can see these are large files and occupy huge storage space on our server. Thankfully my hosting by Dreamhost has unlimited storage space, so I need not worry; but if your hosting has limited storage, it could add to lot of extra charges. I downloaded and tried opening these core files with Wordpad and a mix of gibberish text and symbols appeared.

Core Dump Files

I looked around for possible solutions and found more WordPress bloggers reporting this issue in the WordPress forums. I learnt that these are called Core Dump files and Wikipedia says core dump records the working memory of a computer program usually when the program crashes. Core dumps are often used to diagnose or debug errors in computer programs.

In these forums some people advised we can delete these files and save space after backing up all files and database. Some advise the core files can be read using GDB, the GNU Project debugger. I am not sure if I should delete these files and maybe you can help.

I understand that these files are hosted on our server to keep a record of useful data when the site crashed on a particular day, but I wonder if any hosting engineer is debugging this data or diagnosing why the server or unstable processes crashed or terminated.

Check your WordPress installation and post a comment if you also have “Core” dump files eating your server storage space. What are you going to do about it?


22 comments on “Huge Core Dump Files in WordPress Folders

  1. Carlos says:

    the only dump i know of is when i go to the bathroom.

  2. Jeffro says:

    @Carlos – I guess with a post like this, a comment like that is inevitable!

    @QuickOnlineTips – I maintain a WordPress enthusiast forum which contains quite a few smart people in the world of WordPress. I’ve since created a new thread asking them what these files are and what they do.

    I don’t have any core dump files on my install of WordPress. The only files that reach that size is my error_log which occassionaly I just delete and let it come back.

  3. Kevin says:

    Unless you plan on sending the coredump file to the wordpress/php people to figure out what the problem – or you feel comfortable digging though the debugger – it is perfectly safe to delete. You don’t even have to back anything up. Your host may be interested in the core files – but I doubt it. Most webhost techs wouldn’t be able to step through a debugger, and those that could would probably charge you for it.

    This doesn’t change the fact that something associated with your wordpress install (most likely PHP, but not necessarily) crashed and may do so again. If you aren’t already doing so you should be making backups, and keeping a copy off-site as it sounds like your host may be unstable.

    You might check and see what version of apache, mysql, php, etc… your host has installed and see if there are any known problems/bugs, specifically with wordpress.

  4. Ajay says:

    I don’t think anyone looks at it. But, you should clean these up at regular intervals, unless you have unlimited storage space

  5. Sumesh says:

    I have had core dump files on my design blog(see my author link) and was initially alarmed (whether it was the result of a hack or whatever).

    I asked the question on Twitter. A webdevs and a webhosting employee said that they’re caused by buffer being dumped(whatever that means) and advised me to disable plugins that hog resources.

    I’ve still not found an actual way to prevent it, or understand why it is appearing (I’m not interested in debugging).

  6. QuickOnlineTips says:

    Thanks for all your useful feedback. It seems something is buggy on the wordpress install that is generating these core dumps.

    Obviously no hosting engineer would be interested to look over the code in detail, unless necessary.

    Maybe some plugin is acting funny. I will try to find the problem.

  7. John Hoff - WpBlogHost says:

    Hello, been reading in my reader for awhile but this is my first time commenting.

    I think everyone pretty much has it down. It’s doubtful your host will be interested in these files, as well as you. Deleting them should be fine.

    However, if you’re at all a bit nervous, I’d say back everything up first. Always good to do.

    WordPress on it’s own shouldn’t be dumping a lot of files, I bet it’s a plugin like you suggest.

  8. Paul says:

    You may want to try pulling some plugins down after deleting the core file. My guess is you have a poorly written plugin that’s so hosed it causes the core dump(s) … it’s unlikely that WP itself causes those to happen.

  9. Twilight Fairy says:

    core dump files can be safely deleted, they are useful only if you want to debug what happened. Since WP is pretty much well tested before they release any version, it could be some plugin or some theme component causing the crash. you could send it to the WP guys anyway.

  10. Andy says:

    I’ve been getting masses of these ever since upgrading WP to the latest version. Could WP be to blame? My host is useless when enquiring, they write to bollock me for going over my disk quota and won’t offer any help or advice to resolve the issue. I’m going to start looking for a new host…

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