Category Archives: wordpress

Core Dump files slowing down website

For last few days, or rather weeks, my blog was really slow. Infact the site was throwing resource limit error at times. I contacted my webhosting provider, but they just replied they cannot find anything. So I decided to do some investigation on my own.

First step was to check memory and CPU usage, which turned out to be very high, almost 100%. The fishy thing I figured out was disk space usage, which was way above data I have, so I checked the file system. I figured out hundreds of core.XXXXX files. A little googling showed that these were dump files created by Apache for memory dump, in case some error / crash occured. Deleting these extra files did solve the issue.

More info on the topic

https://wordpress.org/support/topic/hacked-with-strange-core-files

https://wordpress.org/support/topic/arrrg-so-many-core-files

http://en.wikipedia.org/wiki/Core_dump

Taking backup of WordPress site

For sometime now I was planning to try out some things/experimentation with this blog. But before that I wanted to take a backup of whole thing in case I mess up stuff.

Now when I say taking a backup, I am not much worried about wordpress files as such as I know I can just download and install wordpress anytime. Most of the cpanels come with wordpress installation these days or the software can be downloaded from http://wordpress.org/download/. In case you have a customized theme or images, you can simply ftp into your web root folder (www), and copy the wordpress directory to a location where you want to back it up.

For me the only important thing was database. Mostly posts, comments, category and tags. So here are the steps to do that.

  1. Login to your phpmyadmin (or any other way you access your database/ check with your service provider)
  2. Go to your wordpress database, it has tables most probably in form of wp_name. We are concerned about- wp_comments, wp_postmeta, wp_posts, wp_terms, wp_term_relationships, wp_term_taxonomy.
    Note, I am not copying user related or wordpress related information as it is always good to create new information when installing new setup. I am only concerned about the real stuff- post related stuff to be backed up.
  3. Now Click export at the top panelĀ  in PHPMyAdmin. UseĀ  custom as export method.
    Choose the tables you want to export (mentioned above), default format is sql, we can leave that as it is.
    The only thing of concern on this page is “Maximal length of created query” field. I figured out that the default value was too low for me. Adding 2 extra zeros to default “50000” helped me. If your posts are larger, you might need one more zero. The way to check it, is to open the exported sql file and see wp_posts data is available.
  4. Click on Go and you have your backup sql script ready.

Getting the script is one thing and using it another. We need to make sure that the script we just created will actually work. That is simpler than taking backup.

I created a new wordpress installation locally and imported the sql file created above into my new installation.

mysql -u kamal -p -v -h localhost wordpress <D:\data.sql

And this is how my backup blog was ready. That’s it