Racker Hacker

I’ll be taking a short break from posting, but I should be back underway within week!  Here’s what I’m working on during the break:

• MySQLTuner - Thank you for all of the e-mails with suggestions, patches and complaints. The 1.0 version of MySQLTuner is in the works and I hope that it helps you get more done with your MySQL server.
• Boxcheck - A new version of boxcheck.com is coming and it will include more tests for you to use. Also, the tests that it already has will be more reliable. I might even throw in a little AJAX to get everyone excited.
• PleskHacker - I’m still working on the Plesk database documentation, but this project is a lower priority than the first two.

I’m moving into a new house over the weekend, so please don’t be discouraged if you e-mail me and you don’t receive a quick response. For all of the fans of Twitter out there, you can find me on Twitter as RackerHacker.

Normally, qmail will be able to process the mail queue without any interaction from the system administrator, however, if you want to force it to process everything that is in the queue right now, you can do so:

kill -ALRM `pgrep qmail-send`

If for some peculiar reason you don’t have pgrep on your server, you can go about it a slightly different way:

kill -ALRM `ps ax | grep qmail-send | grep -v grep | awk '{print $1}'`

Your logs should begin filling up with data about e-mails rolling through the queue.

Upgrading Plesk from 7.5.x to 8.x will change your Plesk-related MySQL tables from MyISAM to InnoDB. This allows for better concurrency in the Plesk panel when a lot of users are logged in simultaneously. However, some server administrators will disable InnoDB support in MySQL to save resources. This will cause problems after the upgrade.

Plesk may display an error on a white page that looks something like:

Cannot initialize InnoDB

This could mean that InnoDB support was disabled when MySQL was started. To correct this issue, search through the /etc/my.cnf for this line:

skip-innodb

If you find it in your configuration, remove it, and then restart MySQL. To test that InnoDB is enabled, you can refresh the Plesk page, or you can log into MySQL and run SHOW ENGINES. The output from the SHOW ENGINES statement should show YES on the line with InnoDB.

Should DISABLED appear instead, you may have an issue with your InnoDB configuration in your /etc/my.cnf. Be sure to check for innodb_data_file_path and make sure that it is set to an appropriate value.

A value of NO is not a good sign. This means that your version of MySQL was compiled without InnoDB support. This means that it cannot be enabled at runtime because MySQL wasn’t built with any support for InnoDB. Be sure to recompile MySQL with --with-innodb or obtain a new package for your operating system which includes InnoDB support.

If you suspect that your MySQL InnoDB configuration is incorrect, you may want to review this documentation on MySQL’s site:

For MySQL 5: 13.2.3. InnoDB Configuration
For MySQL 4/3.23: 13.2.4. InnoDB Configuration