Databases, Systems & Networks

Source: Visser Labs Blog

When uploading a set of admittedly large images using NextGEN Gallery to my WordPress site I exceeded my web hosts default memory usage allocation for PHP applications. The error was:

Follow thumbnails could not created. sample.jpg (Error : Exceed Memory limit. Require : 80.65 MByte)

This issue can be resolved by increasing the memory usage allocation at a per-plugin level for PHP applications that require more grunt than others. It’s quick and easy!

1. Open an FTP connection to your root WordPress directory
2. Open /wp-content/plugins/nextgen-gallery/lib/gd.thumbnail.inc.php with your favourite text editor (e.g. UltraEdit, etc.)
3. On line #168 un-comment (remove the //) from before @ini_set('memory_limit', '128M');
4. Save and upload changes
5. Delete image/s that failed to generate a thumbnail and re-upload using NextGEN Gallery’s standard Upload Images feature

If you find 128MB is too ‘conservative’ this can be increased again to any figure of your liking, I find 128MB appropriate for most commercial and personal usage but if you’re a HD photographer then you’re going to hit this limit very quickly… that’s it!

Well folks its time that my old home hosted server is retired. Which means I have to migrate all of my 5 websites to a new server. Thanks to the way apache, MySQL WordPress and Drupal work, its easy.

1. Copy Apache Config Files

# ssh username@oldserver
# scp /etc/apache2/sites-available/ user@newserver:/etc/apache2/sites-available/

This will copy all the apache config files over to the new server. Now enable all the sites you copied by creating a symbolic link for each .config file you copied in sites-enabled.

# ln -s /etc/apache2/sites-available/yourwebsite.com.conf /etc/apache2/sites-enabled/yourwebsite.com.conf

or use the command a2ensite which does the same thing for you

# a2ensite yourwebsite.com

Restart apache for the changes to take effect.

# /etc/init.d/apache2 restart

2. Copy Your Websites

# scp -r /var/www/ username@newserver:/var/www

Default WordPress and Drupal installs are just files and we have now copied them across. However all the content, comments etc are stored within MySQL so lets migrate that now.

3. Migrate MySQL

Start by being logged into the old server.

# mysqldump --all-databases -u root -p > backup.sql
# scp backup.sql username@newserver:/home/username/
# ssh username@newserver
# mysql -u root -p < backup.sql

What we did here was use mysqldump to script every database and its contents into several sql commands. Then we copied them to the new server and piped them into the new sql server. All our databases, users and table contents have been imported. Magic.

4. DNS Migration

Now all you need to do is reconfigure your DNS servers to point to the new IP address. Chances are your not hosting your own DNS server so you will have to update them using your provider’s web interface. A word of advice though, create a new entry like test.yourdomain.com and point it to the new server first to make sure everything works.

Plug-ins

Our job as WordPress users (aside from contributing to the WordPress community) is keeping our installs safe from people we do not want to access our sites. There are numerous plug-ins to help shore up our WordPress defenses such as Login LockDown which records IP address and blocks them after a set number of login attempts which helps against brute force attacks. Lire la suite…